Biology Flashcards
The Four Tenets of Cell Theory
- All living things are composed of cells
- The cell is the basic functional unit of life
- Cells only arise from pre-existing cells
- Cells carry genetic info in the form of DNA
Cristae
Folds of the inner mitochondrial membrane
Contains enzymes and molecules essential for ETC
Binary Fission
Replication of prokaryotic cells to form two identical daughter cells
Simpler than mitosis
Method of mitochondrial replication
Peroxisome
Aids in beta-oxidation of very-long-chain fatty acids
Also helps synthesize phospholipids and contains some enzymes for the pentose phosphate pathway
Microtubules
Largest diameter of cytoskeleton filaments. Hollow polymers of tubulin. Motor proteins are kinesin and dynein. Make up flagella and cilia. Organized at centrioles (MTOC)–> attach to sister chromatids during mitosis at their kinetochores and pull them apart.
Microfilaments
Thinnest of the filaments. Polymers of actin. Motor protein in myosin. Roles in muscle contraction and cytokinesis.
Intermediate Filaments
Diverse group of filaments, ranging in diameter. Include keratin, desmin, lamins, and vimentin. Aid in cell to cell adhesions and help maintain the cytoskeleton. Great tensile strength.
Parenchyma
Functional part of an organ. Composed of epithelial cells.
Stroma
Structural tissue of an organ. Composed of connective tissue.
Connective tissue
Cells produce proteins that maintain ECM. Provide structural framework so that epithelial and other cells can carry out organ/structures’ functions. Ex: bone, cartilage, tendons, ligaments, blood, adipose
Archaea
- Usually exist under extreme conditions
- Use alternate energy sources (photosynthetic, chemosynthetic, inorganic compounds from the environment)
- Similar to bacteria because they are single-celled organisms and lack membrane-bound organelles. Also have a circular chromosome
- Similar to eukaryotes because they both have RNA polymerases
- Resistant to many antibiotics
- Reproduce by binary fission/budding
Classification of bacteria by shape
Cocci: spherical
Bacilli: rod-shaped
Spirilli: spiral-shaped
Obligate anaerobes
Organisms that cannot survive in the presence of oxygen
Aerotolerant anaerobes
Anaerobes that are unable to use oxygen in metabolism, but are not harmed by its presence
Facultative anaerobes
Organisms that can toggle back and forth between anaerobic and aerobic metabolism depending on availability of O2
Gram-Positive vs Gram-Negative
Gram-Positive: stain purple, thick cell wall of peptidoglycan, contains lipoteichoic acid
Gram-Negative: stains pink-red, thinner cell wall of peptidoglycan encased by an outer cell membrane, contains phospholipids and lipoproteins (which trigger a relatively dramatic immune response by the host)
Differences between prokaryotes and eukaryotes
- Cell wall
- Membrane-bound organelles / presence of nucleus
- Ribosomal subunit size (30S and 50S in prokaryotes, 40S and 60S in eukaryotes)
- Location of electron transport chain (cell membrane in prok, inner mitochondrial mem in euk)
Genetic Recombination
Transfer of genetic material between prokaryotes. Increases genetic variation. Methods: transformation, conjugation, transduction, transposons
Transformation
Uptake of foreign genetic information from environment
Conjugation
“Mating” of bacteria, Requires contact of two cells. Conjugation bridge forms between donor and acceptor cells. Male (+) donor must have genes for sex factors (usually a plasmid but not always - Hfr).
Transduction
Transfer of genetic material by viral vector (bacteriophage)
Transposons
Genetic elements that can insert or remove themselves from genomes
Hfr cell
Donor cell in which sex factor genes have been integrated into genome. Stands for “high frequency” in terms of conjugation. Engages in conjugation often (what a slutty little Hfr cell)
Bacterial colony growth phases
Lag –> Exponential –> Stationary –> Death
Viral structure
- Can be single- or double-stranded RNA or DNA
- Covered by a protein coat (capsid)
- May be enveloped by lipid-containing shell (makes these viruses more easily attacked)
Positive-sense RNA virus
Virus enters host cell and acts as mRNA, so it can be immediately translated by host cell. Contains genes for its own viral RNA-dependent RNA polymerase
Negative-sense RNA virus
Acts as a template for mRNA that will encode for the “desired” viral proteins. Must contain gene for RNA replicase to ensure that complementary strand is synthesized
Retroviruses
Single-stranded RNA with reverse transcriptase gene. In host cell, complementary DNA is synthesized with the reverse transcriptase. Viral DNA is then incorporated into host cells genome –> gets replicated every cycle of mitosis, host has it forever. Ex: HSV
Lytic cycle
Virus maximizes machinery of the host cell to reproduce as much as possible until the cell bursts and virions are released. Relatively non-advantageous to the virus because then it can no longer use the cell to replicate and spread
Lysogenic cycle
Virus integrates into host cell’s genome and gets replicated every time the cell divides. These viruses are known as proviruses. Infection with one provirus decreases susceptibility of the cell to superinfection (infection with multiple proviruses).
Prions
Proteins that cause misfolding of cells’ proteins. Convert alpha-helices to beta-sheets –> decreases solubility –> causes aggregation that disrupts cell processes
Viroids
Short, circular, single-stranded RNA that silences genes
Ampulla
Widest part of the Fallopian Tube. Location of fertilization
Cortical reaction after penetration by sperm
Release of Ca2+ ions, triggered by the penetration of the cell membrane of the ovum by the sperm. Depolarizes the membrane of the ovum, which prevent fertilization of the ovum by more than one sperm and increases the metabolic rate
Zygote
Fertilized ovum. Officially occurs after depolarization of the ovum membrane. Surrounded by the fertilization membrane
Monochorionic/monoamnionic twins
Monozygotic twins that share the same chorion and amnion
Monochorionic/diamniotic
Identical twins that each have their own amnion but share the same chorion
Dichorionic/diamniotic twins
Monozygotic twins that have different amnions and chorions
Cleavage (embrygenesis)
Rapid mitiotic cell division that occurs as the zygote moves to the uterus. Increases nucleus:cytoplasm and surface area:volume ratios
Indeterminate cleavage
Results in cells that can still develop into complete organisms. Monozygotic twin orginate from indeterminately cleaved cells
Determinate cleavage
Results in cells that are already committed to differentiation into a certain type of cell
Morula
Small solid ball of cells. Immediately after embryo stage. Undergoes blastulation
Blastulation
Morula becomes a hollow ball of cells known as a blastula.
Blastocyst
Mammalian blastula. Hollow mass of trophoplast cells that surround the blastocoel and the inner cell mass
Trophoblast cells
Cells on the outside of the blastula that later give rise to the chorion and placenta
Inner cell mass
Cells of the blastula that protrude into the blastocoel and later give rise to the organism
Chorion
Extraembryonic membrane that develops into the placenta. Contains chorionic villi that penetrate the endometrium
Umbilical cord and its blood vessels
Connects embryo to placenta. Has two arteries and one vein. The vein brings oxygen and nutrient-rich blood from the placenta to embryo. Arteries carry deoxygenated blood and waste back to the placenta
Yolk sac
Site of early blood cell development. Supports the embryo until the placenta is developed
Allantois
Involved in early fluid exchange between the embryo and yolk sac. Surrounded by the amnion and chorion
Amnion
Tough membrane filled with amniotic fluid. Serves as a shock absorber to protect the embryo
Gastrulation
Generation of three distinct cell layers
Archenteron
The membrane invagination into the blastocoel during gastrulation. Later develops into the gut
Blastophore
Opening of the archenteron. In deuterostomes like humans, it develops into the anus
Ectoderm
Outer-most germ layer. Includes skin, hair, nails, face, lens of the eye, lower anal canal. Also includes the nervous system, adrenal medulla, and inner ear
Mesoderm
Middle germ layer of cells. Includes bones, muscles, circulatory system, gonads. Specifically includes connective tissue of the digestive and respiratory systems and the adrenal cortex
Endoderm
Inner-most germ layer. The linings of the digestive and respiratory tracts and their accessory organs
Germ layer of the adrenal medulla
Ectoderm
Germ layer of the adrenal cortex
Mesoderm
The process of fetal nerve development
Neurulation. Notochord (mesodermal cell) forms, forming the long axis of the organism. Then induces overlying ectodermal cells to form neural folds surrounding neural grooves. The folds grow and fuse into the neural tube, which gives rise to the CNS. Each fold has a neural crest cell at the tip, which migrate outward to form the PNS. Finally, ectodermal cells migrate over the neural tube to cover the NS.
Neural crest cells
Located at the tips of the neural folds. Migrate outward to form the PNS
Neural tube
Gives rise to the CNS. Made by fusion of neural folds. Made of ectodermal cells
Teratogens
Substances that interfere with embryonic development. Ex: alcohol, drugs, viruses, bacteria, and environmental toxins
Spina Bifida
Birth defect. Exposure of some portion or all of the spinal cord to the outside world. Due to maternal deficiency in folic acid. Wide range of severity of effects
Induction
Ability of one group of cells to influence the differentiation of nearby cells in embryonic development
Stages of cell specialization
- Specification: reversilby designated as a certain cell type
- Determination: irreversibly committed to a specific lineage, may be due to morphogens
- Differentiation: the cell actually changing structure, function, and biochemistry to be able to achieve a certain function
The first instance of differentiation in embryonic development
After the 16-cell stage of the morula. Differentiates into trophoblast cells or inner cell mass
Potency of Adult Stem Cells
Multipotent
Morphogens and common examples
Molecules that cause determination of cells. Ex: TGF-beta, sonic hedgehog (Shh), and epidermal growth factor (EGF)
Inducers
Growtth factors that induce differentiation or mitosis
Complete regeneration
Re-growth of damaged/removed tissue with identical tissue
Incomplete regeneration
Repair of damaged or removed tissue with non-identical tissue
Senescence
Biological aging at cellular and organism levels. At cellular levels, cells no longer divide possibly due to shortened telomeres
Telomerase
A reverse transcriptase that synthesizes the ends of chromosomes to prevent senescence. Found in germ cells, fetal cells, and tumore cells
Roles of the Placenta
Prevents mixing of fetal and maternal blood. Allows diffusion of O2, nutrients, antibodies, and waste (for removal)
Umbilical arteries
- Carry de-oxygenated blood away from the fetus.
Umbilical vein
Only 1. Carries oxygen and nutrient-rich blood from the placenta to the fetus
Fetal Shunts
Three of them: foramen ovale, ductus arteriosus, ductus venosus. Developed by the fetus to bypass slow-developing organs upon which it does not rely. These organs are the lungs and liver.
Foramen ovale
Shunt in fetuses that connects the right atrium to the left atrium to bypass the right ventricle. Thus the blood is pumped through the aorta instead of the pulmonary system (avoids the lungs)
Ductus arteriosus
In fetal development, shunts leftover blood from the pulmonary artery to the aorta
Ductus venosus
In fetal development. Causes blood to bypass the liver by shunting blood from the placenta (in the umbilical vein) directly into the inferior vena cava.
Key Features of the First Trimester
Development of the heart, eyes, gonads, limbs, and liver. Cartilaginous skeleton begins to harden into bone. Brain is fairly developed by the end
Key Features of the Second Trimester
A lot fo growth. Face takes on human appearance. Fingers and toes elongate
Key Features of Third Trimester
Further rapid growth and brain development (although growth slows right before birth). Selective transport of antibodies from the mother.
Parturition
Vaginal childbirth
Hormones involved in childbirth
Prostaglandins and oxytocin. Control the rhythmic contractions of uterine muscle (smooth muscle)
Nerves vs Tracts
Nerves are in the PNS and can carry more than one type of information, their cell bodies are grouped together in ganglia. Tracts are in the CNS and can only carry one type of information, and their cell bodies are grouped in nuclei.
Location of most ribosomes and ER in neurons
Soma
Axon hillock
Transition region of the neuron from soma to axon. Function: integrating incoming signals and triggering AP if appropriate
Astrocytes
Nourish neurons and for the blood-brain barrier
Blood-brain barrier
Controls the transmission of solutes from the bloodstream into nervous tissue
Ependymal cells
Line the vetnricles of the brain and produce cerebrospinal fluid
Cerebrospinal fluid
Physically supports the brain and acts as a shock-absorber
Microglia
Phagocytic cells that ingest and break down waste products and pathogens in the CNS
Oligodendrocytes vs Schwann cells
Both produce myelin for neurons. Oligodendrocytes are in the CNS and Schwann are in the PNS
Types of glial cells/neuroglia
Astrocytes, ependymal cells, microglia, oligodendrocytes, Schwann cells
Methods of neurotransmitter-removal from the synapse
Enzymatic breakdown (ex: ACh), reuptake carriers taking leftover NT back into the presynaptic cell (ex: NE, dopamine, serotonin), or simple diffusion away from the synapse (ex: NO)
Supraspinal circuits
Neural pathways that involve the brain/brainstem
White matter
Axons encased in myelin sheaths. Found on the inside of the brain and the outside of the spinal cord.
Grey matter
Made of neural dendrites and unmyelinated cell bodies. Found on the surface of the brain and in the middle of the spinal cord
Dorsal root ganglia
Cell bodies of sensory neurons entering the spinal cord
Vagus nerve
Cranial nerve X. Responsible for parasympathetic innervation of the thoracic abdominal cavity
Neurotransmitter of the Parasympathetic NS vs Sympathetic NS
Para: both pre- and postganglionic neurons release ACh.
Sympathetic: preganglionic neuron releases ACh, postganglionic neuron releases NE
Temporal summation
Integration of multiple neural signals near each other in time
Spatial summation
Refers to the addition of multiple signals near each other in time
Haploid
Only having one of each chromosome in a pair. Germ cells/gametes are haploid
Restriction Points in Mitosis
G1->S: Controlled by p53. Also G2->M: checks for enough organelles and cytoplasm
S phase
Results in every chromatid being replicated and then boudn with its identical sister chromatid at the centromere
What proteins control progression of the cell cycle?\
Cyclins, CDKs, transcription factors
Prophase
Chromatin condenses into chromosomes. Polarization of centrioles/MTOC occurs (found in centrosomes, outside nucleus). Nuclear membrane dissolves, allowing microtubules to connect centrosomes to chromosomes at the kinetochores. Mitotic spindle forms
Metaphase
Kinetochores fibres align the chromosomes at the metaphase plate (equitorial plate)
Anaphase
Kinetochore fibres shorten, pulling apart sister chromatids
Telophase
Reverse of prophase: chromosomes uncoil, spindle disappears, new nuclear membrane forms
Cytokinesis
Separation of cytoplasm and organelles through pinching of dinucleate cell by actin ring
Meiosis I
Separation of homologous chromosomes. Results in haploid daughter cells.
Reductional division
Cell division that results in decrease of ploidy
Meiosis II
Separation fo identical sister chromatids. No change in ploid (haploid).
Equatorial Division
Ploidy is conserved in this kind of cell division
Prophase I
Condensation of chromatin into chromosomes. Nuclear mem dissolves, Meiotic spindle forms. Crossing over occurs
Metaphase I
Different from mitosis because here, homolgs align across from each other on either side of the metaphase plate and are held by 1 spindle fibre, not 2
Pathway fo Sperm
SEVE(N) UP:
seminiferous tubules, epididymis, vas deferens, ejaculatory duct, (nothing), urethra, penis
Semen
Sperm mixed with seminal fluid: a mix of fluids from seminal vesicles (fructose), prostrate gland (provide alkaline properties), and bulbouretrhal gland (lubricant)
Spermatogenesis
- Spermatogonia (diploid stem cell) goes through S stage to form…
- Primary spermatocyte (diploid) goes through meiosis I to form…
- Secondary spermatocyte (haploid) goes through meiosis II to form…
- Spermati (haploid) goes through maturation to form…
- Spermatozoa
Ovaries
Produce estrogen and progesterone. Filled with thousands of follicles (that will eventually give rise to eggs_
Follicles
Nourish and protect ova (eggs)
Ovulation
1 egg is released from follicle into the peritoneal sac/abdominal cavity. Then gets drawn into the fallopial tube/oviduct that leads into the uterus.
Oogenesis
- Primary oocyte (2n and arrested in prophase I) undergoes Meiosis I to become…
- Secondary oocyte (n) only proceeds through metaphase II if sperm penetrates the sona pellucida and corona radiata, so that it then becomes…
- Mature ovum (n) then completes meiosis II to become a zygote
Roles of LH and FSH in Male Sexual Development
Both released from anterior pituitary is response to GnRH from hypthalamus
LH: Triggers increased testosterone production in the Cells of Leydig in the testes
FSH: Stimulates Sertoli cells and ups sperm maturation
Roles of LH and FSH in Female Sexual Development
Both released from anterior pituitary is response to GnRH from hypthalamus
LH: Triggers release of progesterone from corpus luteum
FSH: Triggers increased production of estrogens
Estrogen
In embryos, causes reproductive tract to develop. In adults, causes thickening of the uterin lining (endometrium) each month.
Progesterone
Helps maintain and develop endometrium (but not the initial thickening - that is estrogen). By the end of the first trimester, it is released from the placenta rather than the corpus luteum.
Menstrual cycle hormone levels by stage
Follicular phase: estrogen and progesterone are low. GnRH, LH, and FSH are on the rise. Rising estrogen levels cause GnRH, LH, FSH to level off
Ovulation: Estrogen levels have gotten so high that is now causes (+) feedback-> SPIKE in FSH, LH, GnRH. Surge of LH triggers release of ovum from ovary to abdominal cavity
Luteal phase: Estrogen remains high. Progesterone steadily climbs (motivated by LH). Neg feedback causes decline of GnRH, LH, and FSH
Mestruation (no implantation): decrease in LH then progesterone, and eventually a rise in GnRH for next cycle
Hormones in pregnancy
Blastocyst secretes human chorionic gonadotropin (hCG) - very similar to LH.
Human chorionic gonatotropin (hCG)
Responsible for maintining release of progesteron from the corpus luteum during first trimester until the placenta is developed enough. Released from blastocyst. Only possible it zygote implants in endometrium. Very similar to LH.
Menopause
Ovaries become less sensitive to FSH and LH
Compare durations of effects of peptide hormones vs. steroid hormones
Peptide hormones’ effects usually have rapid onset but are short lived, whereas steroid hormones are slower to take effect but sustain for longer period of time
Direct hormones
Have major effect on non-endocrine tissues
Tropic hormones
Have major effect on other endocrine tissues
Albumin
A nonspecific steroid hormone carrier protein
Are steroid hormones active when bound to their carrier proteins?
No
What are the catecholamine hormones
Epinephrine and norepinephrine
Thyroxine and triiodothyronine
Thyroid hormones that regulate metabolic rate. They are amino acid derivatives. Effects are slow in onset but are long lasting
Hypothalamus
Gland in the brain that serves as the bridge between the nervous and endocrine systems. Secretes tropic hormones that act on the anterior pituitary
GnRH
Gonadotropin-releasing hormone. Released from hypothalamus. Stimulates release of FSH and LH from anterior pituitary
GHRH
Growth hormone-releasing hormone. Released from hypothalamus. Stimulates release ofgrowth hormone from the anterior pituitary
TRH
Thyroid-releasing hormone. Released from hypothalamus. Stimulates release of TSH from anterior pituitary.
CRF
Corticotropin-releasing factor. Released from hypothalamus. Stimulates release of ACTH (adrenocorticotropic hormone) from anterior pituitary
PIF
Prolactin-inhibiting factor. It is actually dopamine released from the hypothalamus. Inhibits the release of prolactin from the anterior pituitary
Hypophyseal Portal System
Blood vessels between the hypothalamus and the anterior pituitary
How does the hypothalamus signal release of hormones from the posterior pituitary? Which hormones?
Axons of the neurons of the hypothalamus extend down to the posterior pituitary and signal release of oxytocin and antidiuretic hormone (ADH/vasopressin)
Oxytocin
Produced by hypothalamus but secreted by posterior pituitary. Stimulates uterine contractions during labor and milk letdown during lactation. Also plays a role in bonding.
Vasopressin
AKA antiduretic hormone (ADH). Release is motivated by excessively high osmolarity of the blood. ADH causes increased water resorption by the kidneys to decrease osmolarity of the blood. Produced by hypothalamus but secreted by posterior pituitary
Prolactin
Stimulates milk production by acting directly on the mammary glands. Released by the anterior pituitary when dopamine levels decrease. Dopamine has an inhibitory effect on the release of prolactin.
Endorphins
Decrease the perception of pain. Released from the anterior pituitary. The action of endorphins is mimicked by morphine
Growth Hormone
Released from the anterior pituitary. Promotes the growth of bone and muscle by preventing the uptake of glucose in the tissues that are not growing and stimulating the breakdown of fatty acids to increase the availability of glucose for bones and muscles
Epiphyseal plates
The regions of origin of bone growth. They seal shut during puberty
Gigantism
Condition characterized by excess growth hormone in children before their epiphyseal plates seal shut
Dwarfism
Deficit in growth hormone before a child’s epiphyseal plates shut.
Acromegaly
Excess levels of growth hormone in adults (after shutting of epiphyseal plates). Excessive growth of smaller bones mainly in hands, feet, and head
What events and receptors trigger the release of ADH (and from where)?
Triggers: low blood volume sensed by the baroreceptors, or high blood osmolarity as sensed by the osmoreceptors
ADH is produced in the hypothalamus but secreted from the posterior pituitary
Mechanism of action of ADH
Increases the permeability of the collecting duct so that more water is absorbed from the filtrate in the nephron –> more water is retained in the body
Positive feedback loop of ____ (hormone involved in smooth muscle contraction)
Oxytocin; positive feedback loop exists in that the uterine contractions stimulated by oxytocin trigger the release of more oxytocin, which causes stronger and stronger contractions
Function of the thyroid
Setting basal metabolic rate, promoting calcium homeostasis
Triiodothyronine and thyroxine
Amino acid hormones released by the thyroid that set basal metabolic rate by increasing cellular respiration. Formed by iodination of the tyrosine in the follicular cells of the thyroid.
Calcitonin
Release from the thyroid gland is triggered by high levels of Ca2+ in the blood. Increases Ca2+ excretion from the kidneys, decreases Ca2+ absorption in the gut, and increases storage of Ca2+ in the bone
Hypothyroidism
Deficiency of thyroid hormones. Characterized by being cold/lowered body temperature, slowed respiratory rate and HR, weight gain, and lethargy.
Hyperthyroidism
Excessive amounts of thyroid hormone. Symptoms include increased body temp/being hot all the time, weight loss, increased breathing and heart rates, and heightened activity level
Parathyroid hormone
Counteracts calcitonin to increase levels of Ca2+ in the blood. Does so by decreasing Ca2+ excretion in the kidneys, increasing absorption of Ca2+ in the gut (via Vitamin D), and increasing resorption of Ca2+ in the bones (releasing it into the blood)
Regulates Phosphorus homeostasis by increasing resorption of phosphate from bone and decreasing reabsorption in the kidney (increases the phosphate excreted in urine). They cancel each other out so that there are no drastic changes in phosphate levels
Activates vitamin D which is required for absorption of Ca2+ and PO4^2- in the gut.
Corticoids (place of secretion and the three classes)
Secreted from the adrenal cortex. Classes: glucocorticoids, mineral corticoids, and cortical sex hormones
Glucocorticoids - the two main ones
Cortisone and cortisol. They are corticosteroids released from the adrenal cortex that regulate blood glucose by increasing gluconeogenesis and decrease protein synthesis. Also decrease inflammation and the immunological response. Cortisone is a “stress hormone”
Mineralocorticoids - main example
Govern salt and water homeostasis. The main ex. is aldosterone, which increases Na+ reabsorption and decreases reabsorption of K+ and H+ in the distal convoluted tubule and collecting duct of the nephron.
Results in more K+ and H+, and less Na+ excreted in the urine
Describe the system that governs release of aldosterone
Renin-angiotensin-aldosteron system.
Low BP causes the juxtaglomerular cells of the kidney to secrete renin. Renin cleaves angiotensinogen (previously inactive) into angiotensin I. Angiotensin-converting enzyme (ACE) in the lungs converts angiotensin I to angiotensin II, which then triggers the cortex to release aldosterone to motivate Na+ and water reabsorption in the nephron –> increases blood volume –> increases blood pressure
Cortical sex hormones
Androgens and estrogens. Plays a smaller role in male physiology because the testes secrete so much testosterone and other androgens.
The 3 Functions of Corticosteroids (the 3 S’s)
Sugar (glucocorticoids)
Salt (mineralocorticoids, mainly aldosterone)
Sex (cortical sex hormones)
Catecholamines
Class of amino acid-derived molecules, specifically, epinephrine and norepinephrine which trigger the sympathetic NS.
Islets of Langerhans - the types of cells and what they secrete
Hormone-producing cells in the pancreas. Three types: alpha (secretes glucagon), beta (secretes insulin), and delta (secretes somatostatin)
Glucagon
Increases blood glucose levels during times of fasting by triggering glycogenolysis, gluconeogenesis, and degradation of protein and fat
Insulin
Counteracts glucagon. Induces muscle and liver cells to take up glucose from the blood and store it as glycogen. Also induces fat and protein synthesis
Polyuria and polydipsia in diabetes mellitus
Increased urination and thirst (respectively) because the the excessive amount of glucose in the blood overwhelms the kidneys’ filtration system, so glucose winds up in the urine and takes too much water with it because glucose is osmotically active (ie urine concentration increases greatly in DM patients)
Type I Diabetes
Autoimmune destruction of beta cells in the pancreas. Low or absent levels of insulin. Treatment involves insulin injections
Type II Diabetes
Insulin receptors become desensitized to insulin due to high-carb diets and obesity (as well as genetic factors). Insulin cannot affect cells, so they do not take in glucose, thus keeping blood glucose levels high. Treatment involves lifestyle changes and medications that help the body use the insulin it produces
Somatostatin
Inhibitor of both insulin and glucagon secretion. Release is triggered by high blood glucose and high amino acid concentrations. Secreted by both the pancreas and the hypothalamus (where is inhibits the release of growth hormone)
Gonadotropins
LH and FSH
In males, trigger release of testosterone from the testes. In females, trigger release of estrogen and progesterone from the ovaries.
Pineal gland
Deep in the brain. Secretes melatonin, which likely regulates circadian rhythms. Also receives projections from the retina but is not involved in vision (likely means that pineal gland reacts to darkness and may cause “sleepiness”)
Erythropoietin
Hormone produced in the kidneys that stimulates bone marrow to produce more RBCs. Secreted in response to low O2 levels in the blood
Atrial natriuretic peptide
ANP. Released from the heart when chamber cells are stretched due to excess blood volume. Acts to increase Na+ excretion (increases urine volume, decrease blood volume and thus, pressure)
Nares
AKA nostrils
Vibrissae
Nasal hairs
Pharynx vs Larynx
Pharynx is located behind the nasal cavity and is allows passage of air and food.
Larynx is designed only for the flow of air. The opening is covered by the epiglottis to keep food out of the respiratory tract. Contains vocal cords
Trachea
Cartilaginous structure of respiratory tract through which air passes after the larynx.
Flow of air during inhalation
Nares -> Pharynx -> Larynx -> one of the two bronchi -> bronchioles -> alveoli
Surfactant
Detergent that covers alveoli, reducing surface tension.
Pleurae
The membranous sacs surrounding each lung
Visceral pleura
The surface of the pleura that is adjacent to the lungs. Innermost surface of the intrapleural space
Parietal pleura
The surface of the pleura that lines the chest cavity
Intrapleural space
Space within the membranous sacs (pleurae) surrounding each lung. Filled with a thin layer of fluid
Muscles responsible for inhalation
Diaphragm and external intercostal muscles
What is the driving force of air rushing into the lungs during inhalation?
The low pressure in the intrapleural space compared to the lungs: Upon inhalation, the diaphragm flattens and the volume of the chest cavity increases, thus decreasing pressure in the intrapleural space, allowing the lungs to expand, then decreasing the pressure inside the lungs below atmospheric pressure. Air rushes into the lungs from the atmosphere
Mechanism of Exhalation
Does not have to be an active process. Relaxation of the diaphragm and external intercostals causes decrease in chest cavity volume -> increase in intrapleural pressure -> this along with the recoil of the lungs causes the lung pressure to exceed atmospheric –> pushes air out of lungs
How does one speed up exhalation?
Contraction of the internal intercostal muscles and abdominal muscle. They oppose the external intercostals and pull the rib cage down.
Vital Capacity
The difference between maximum and minimum volume of air in the lungs
VC = total lung capacity (TLC) - residual volume (RV)
Tidal volume
Volume of air inhaled or exhaled in a normal breath
Expiratory reserve volume
Volume of additional air that can be forcibly inhaled after a normal inhalation
Inspiratory reserve volume
Volume of additional air that can be forcibly inhaled after a normal inhalation
Ventilation center
Control center of breathing. Neurons in the medulla oblongata. Respond to the response of chemoreceptors that are sensitive primarily to high partial pressures of CO2.
When CO2 concentration is too high (hypercarbia), ventilation center will increase respiratory rate in order to exhale more CO2
Driving force behind gas exchange
Difference in partial pressures of O2 and CO2 between the deoxygenated blood that arrives at the alveoli and inside the alveoli themselves
Natural respiratory response to increased altitude where less oxygen is available
Body increases respiratory rate to try and get more oxygen into the body –> decreases CO2 concentration –> Hb is triggered holds on more tightly to oxygen rather than release it to the blood. To make up for this, the body makes more RBCs in order to increase O2 delivery to the cells
Thermoregulation via the repiratory system
Vasodilation (dissipates heat) and vasoconstriction (conserves heat) in the capillaries of the nasal cavity and trachea. Resp system can also transfer heat to the environment through the evaporation of water in mucous secretions (ex: dogs panting)
Lysozyme
Enzyme present in the nasal cavity that attacks the peptidoglycan cell walls of gram-positive bacteria
Mucociliary escalator
Refers to the mechanism of mucous in the airway trapping foreign matter, then cilia propelling the mucus up to the oral cavity to be swallowed or expelled.
Immune cells of the lungs
Macrophages: engulf and digest pathogens, signal the rest of the immune system that there is an invader.
Mast cells: have pre-made antibodies on their surfaces, so when the right substance bonds to the antibody, an immune response is induced. These antibodies are responsive to pollens and molds
Respiratory response to acidemia
High H+ is sensed by the chemoreceptors in the blood-brain barrier –> increases respiratory rate to decrease [CO2], which promotes the bicarbonate buffer system in the blood to shift to in the direction that consumes H+.
Spirometer
Can measure 3 out of 4 lung volumes: inspiratory reserve, exhilatory reserve, and tidal volumes, but cannot measure residual volume
Atrioventricular valves
Separate the ventricles from the atria. The tricuspid valve (right) and the mitral/bicuspid valve (left)
Semilunar valves
Separate the ventricles from the vasculature. Pulmonary valve (right) and aortic valve (left)
Mitral valve
AKA bicuspid valve. Separates the left atrium and ventricle (blood flows from atrium to ventricle)
Tricuspid valve
Separates the right atrium and right ventricle
Pulmonary valve
Separates the right ventricle from the pulmonary circuit
Systole
Period of ventricular contraction. AV Nodes close and blood is pumped out of the ventricles
Atrial kick
Additional amount of blood that is forcefully pushed into the ventricles by atrial systole. About 5-30% of cardiac output
SA Node
Origin of electrical impulses in the heart. Generates 60-100 signals per minute without requiring any stimulation. Located in the wall of the right atrium
AV Node
Stimulated by the SA Node. Sits at the junction of the atria and ventricles. Signal is slightly delayed here in order to allow the ventricles to fill completely before they contract
Bundle of His
Receives stimulation from the AV Node. Located in the interventricular septum (wall). Passes signals on to the Purkinje Fibers
Perkinje Fibers
Distribute electrical signal evenly throughout ventricular muscle.
Intercalated discs in cardiac muscle (definition and function)
Connect the cardiac muscle cells, many through gap junctions so that their cytoplasms are connected. This allows coordinated ventricular contraction
Myogenic activity
Possessed by the heart in that it does not need any neurological input to contract.
Vagus Nerve
Parasympathetic innervation of the heart
Diastole
Semilunar valves are closed as the ventricles fill with blood from the atria. Pressure decreases during relaxation
Cardiac output and stroke volume
CO: Total blood volume pumped by a ventricle in a minute.
SV: Volume of blood pumped out of the heart by a single beta
CO = HR * SV
CO is usually about 5 liters per minute
Endothelial cells (and their role in vasculature)
These cells line all blood vessels. They are able to secrete chemicals that control vasodilation/vasoconstriction, allow WBCs to pass through during inflammation, and release chemicals that aid in blood clotting in the event of a wound.
Compare: elasticity, resistance to flow, and mechanism of blood movement of arteries and veins
Arteries: highly elastic, thick smooth muscle walls, high resistance to flow, elastic recoil of the walls keeps arterial pressure high
Veins: inelastic, although they can stretch to accommodate HIGH volumes of blood - so low resistance. Blood movement is governed by skeletal muscle movements and valves to prevent backflow.
Varicose veins
Veins that become enlarged where blood has pooled due to failed valves. Women are at higher risk of developing them during pregnancy because of increased total blood volume and the fetus pushing on their inferior vena cava
Portal systems (and what are the three in the body?)
Connections of two distinct capillary beds in series (may be separated by vessels in between)
Three in the human body: hepatic, hypophyseal, and renal portal systems
Hepatic portal system
Blood leaving the capillary bed of the gut will go through the hepatic portal vein and then the hepatic capillary bed before returning the heart
Hypophyseal portal system
Allows for paracrine signaling of the hypothalamus directed onto the anterior pituitary. Capillary bed on the hypothalamus connects directly to the capillary system on the anterior pituitary
Renal portal system
Blood leaving the capillaries of the glomerulus enters an efferent arteriole before surrounding the nephron in the vasa recta (a second capillary bed)
Hematopoietic cells
Stem cells in bone marrow that give rise to all blood cells (RBCs, WBCs, and platelets)
Functions of erythrocyte structure/makeup/shape
Biconcave because it increases surface area, allows passage through tiny capillaries, lack of membrane-bound organelles allows maximum space for Hb molecules, and lack of mitochondria specifically means that the cells will not use up the O2 they are carrying.
Spleen
Recycles RBCs because they cannot divide (due to no nucleus)
Hematocrit
Refers to the percentage of blood that is red blood cells. Normal ranges are females 36-46% and males 41-53%
Hemoglobin
Molecules within RBCs that bind to O2 for transport.
Normal ranges in females and males are 12-16 g-dL and 13.5-17.7 g/dL, respectively
Granulocytes (def. and the types)
Leukocytes that contain cytoplasmic granules that contain compounds that are toxic to foreign invaders. Involved in allergic reactions, allergies, pus formation, and destruction of bacteria.
Types: neutrophils, eosinophils, basophils
Agranulocytes
WBCs that do not contain granules
Monocytes/macrophages and lymphocytes (T and B cells)
Different sites of maturation of lymphocytes
B-cells matured in the bone marrow.
T-cells matured in the thymus
Macrophages (def and examples)
Phagocytose foreign matter, like bacteria. Each organ’s macrophages have their own name. Ex:
Microglia in brain
Langerhans cells in skin
Osteoclasts in bone
Erythropoietin
Hematopoietic chemical released by the kidney that stimulates RBC development
____ are the surface proteins of RBCs, and include A, B, and O
antigens
Hemolysis
Rupture or destruction of blood cells. Occurs if a person receives the wrong blood type (i.e. patient with type A blood receives anti-A antibodies from either B blood or AB blood, which trigger an immunes response because the proteins appear to be foreign)
People with type B blood naturally produce anti- __ antibodies
A
Rh factor
Signifies the presence (Rh+) or absence (Rh-) of the D allele. Mainly important in maternal/fetal medicine.
Erythroblastosis fetalis
Condition in which the mother is Rh- and the fetus is Rh+. Anti-Rh antibodies produced by the mother can diffuse into fetal blood through the placenta and cause hemolysis (fatal to the fetus). Today it is preventable by medicine. It is only a problem after the first child because the mother will not start making the fatal antibodies until after the gestation period (it is an issue for any future pregancies)
Sphygmomanometer
Measures the gauge pressure in the systemic circulation
Blood pressure is expressed as the ratio between…
Systolic pressure (ventricular contraction) to diastolic pressure (ventricular relaxation)
In which vascular structure is the largest drop in blood pressure
Arterioles
Pressure differential equation (blood pressure)
delta P = CO * TPR
TPR = total peripheral resistance
What cells and what conditions trigger the renin-angiotensin-aldosterone system?
Low perfusion past the juxtaglomerular cells of the kidney
Oxygen saturation
The percentage of Hb molecules in the blood saturated by oxygen
Structure of Hb
Each Hb has 4 heme groups, each of which contain a central iron atom that undergoes changes in oxidation state to bind to O2
Predominant form of CO2 in the blood
bicarbonate ion (HCO3-)
Carbonic anhydrase
Catalyzes the reaction of CO2 and water to form carbonic acid (a weak acid)
Effect of decreased pH on Hb-O2 binding affinity
The increased concentration of H+ allows H+ to bind to Hb and lower its affinity for O2 –> shifts Hb curve right (this is the Bohr effect)
Bohr effect
increased acidity of the blood leaving to a rightward shift in Hb-O2 binding curve (greater unloading of O2 to the tissues, as is what happens and what it needed after during high intensity exercise, which produces CO2 and lactic acid)
Fetal Hb has a ___ affinity for oxygen. Why
Lower - because fetuses lack 2,3-BPG (2,3-biphosphoglycerate) which decreases the binding affinity of Hb for O2.
How do carbohydrates, amino acids, and fats enter the bloodstream from the GI tract?
Carbs and am. acids: diffuse into capillaries at small intestine and then enter circulation via hepatic portal system
Fats: get absorbed into lacteals in small intestine, bypassing the hepatic portal system via the thoracic duct, where they are packaged into lipoproteins
Starling forces (describe the opposing pressures)
Hydrostatic: This is the pressure of the fluid pushing out on the blood vessel walls. Generated by contraction of the heart and the elasticity of the arteries. Greater than osmotic pressure on the arteriole side of capillary beds, but then drops below it on the venule side as elasticity decreases
Osmotic/oncotic: The “sucking” pressure of the solutes in the blood, motivating water to flow into the bloodstream to dilute blood concentration (mainly of plasma proteins). Remains constant
Lymph (and how is it returned to the bloodstream?)
Fluid of the lymphatic system, which takes up interstitial fluid and recycles it. Lymph is returned to the bloodstream through the thoracic duct
Components of blood clots
Coagulation factor proteins and platelets
Tissue factor
A protein that is exposed when blood vessels are damaged. Sensed by coagulation factors, signaling their release from the liver, in the same way that platelets recognize collagen upon vessel damage.
Thrombin
Major player in coagulation. It is activated by thromboplastin from prothrombin. It is able to convert fibrinogen to fibrin
Fibrin
Clot-formation protein. Activated by thrombin. Causes aggregation of fibers into a net that catches RBCs and other platelets to form a stable clot over the damage.
Thrombus formation
blood clotting
alpha_IIb-beta_3 integrin molecules
Adhere to fibrinogen to help form bridges between platelets in scabs.
Plasmin
Protein that achieves breakdown of blood clots. Formed through activation of plasminogen
Which blood type can be given to a patient without knowing their blood type?
O-
Lymph nodes
Location for communication between immune cells so that they can mound an attack. B-cells can be activated here
Gut-associated lymphoid tissue (GALT)
Immune tissue in close proximity to the GI tract. Specifically includes tonsils, adenoids, Peyer’s patches and lymphoid aggregates int eh appendix
T/F: eosinophils are granulocytes
TRUE: the only granulocytes are eosinophils, basophils, and neutrophils; all the rest of the immune system cells are agranulocytes
Defensins
Antibacterial enzymes found on the skin
Lysozyme
A nonspecific bacterial enzyme that is secreted in saliva and tears
n
Cell-mediated immunity
Subsection of the specific immune response driven by T-cells
Humoral immunity
Subsection of the specific immune response driven by B-cells. Called humoral because the antibodies dissolve in the blood rather than inside of the specified cell
Complement system
Nonspecific response component involving a set of proteins that can punch holes in the cells walls of bacteria
Interferons
Proteins that prevent viral replication and dispersion. Cause neighboring cells to produce less viral and cellular proteins, as well as decrease the permeability of the cells, making it harder for a virus to infect them. They also upregulate MHC class I and II which increases antigen presentation and detection of the infected cells by the immune system. Interferons are responsible for many of the flu-like symptoms present due to viral infection
Macrophages
Always present in tissue in inactive form –> gets activated upon infection –> phagocytoses invader via endocytosis –> digests it with enzymes–> MHC binds to antigens and presents them on the surface of the cell
MHC I vs MHC II
I: present in ALL nucleated cells in the body. MHC-I pathway is known as the endogenous pathway because any protein produced or processed (like an antigen digested from a pathogen) within a cell can be presented by MHC I. Triggers killer T cells
II: only present in antigen-presenting cells like macrophages, dendritic cells, and some B- and skin cells. Takes in antigens from the environment and then presents them on the surface to trigger BOTH adaptive and innate responses. “Exogenous pathway” because the antigen was in antigen-form prior to being taken up by the cell.
Pattern recognition receptors / toll-like receptors
TLRs and the most well-known PRRs on the surfaces of dendritic cells and macrophages. PRRs are able to recognize the type of invader in order to trigger production of the correct cytokines to recruit the right types of immune cells
NK cells
Natural killer cells that are able to detect the down-regulation of MHC (characteristic in infected and cancer cells) and trigger apoptosis to minimize overall damage of other cells
Neutrophils
Most popular leukocyte in the blood and are very short-lived. Phagocytic, and they target bacteria, following them via chemotaxis, up the concentration gradient of the bacteria until they find the source. Neutrophils can also find bacteria that have been opsonized by B-cells (marked with an antibody by a B-cell). Dead neutrophil accumulation forms pus
Pus
Accumulation of dead neutrophils
Opsonization
Marking of a cell with an antibody
Eosinophils
Mainly involved in allergic response. Release large amounts of histamine, which enhances immune responses by vasodilating and increasing leakiness of the blood vessels –> inflammation
Basophils
Less common player in allergic responses. Low population in the blood when the immune system is at rest, Have large, purple granules. Closely related to mast cells. Relase histamines
Mast cells
Granulocytes with small granules. Exist in the lungs, mucosa, and epithelium. Release histamines in response to allergens –> inflammatory response
Antibody structure
Y-shaped with two light and two heavy chains held together by disulfide and non-covalent interactions
Naive B-cells undergo ____ and the ____ region in order to produce the correct antibodies against the pathogen at hand
Hypermutation; antigen-binding region
Isotype switching
Process of cells switching which type of antibody (5 types) they produce based on the type of cytokine that is stimulating them
Describe the two daughter cells that are produced from proliferation of a naive B-cell
Plasma cell: produces large amounts of antibodies. eventually die
Memory B-cell: Stays in the lymph node, waiting for re-exposure to the same antigen. can last a lifetime
Positive selection of T-cells
Allowing the maturation of only the T-cells that can respond to the presentation of the antigen on MHC
Negative selection of T-cells
Causing apoptosis in cells that are activated by proteins produced by the organism itself (self-activating)
Thymosin
Peptide hormone that facilitates T-cell maturation. Secreted by thymic cells
Helper T-cells
Present CD4+ cell markers. Recruit other immune cells. These cells are lost in HIV and prevents the immune system from mounting an appropriate response to infection. Respond to antigens presented on MHC-II molecules (exogenous antigen-presenting –> so these cells are most effective again bacterial, fungal, and parasitic infections)
Cytotoxic T-cells
Present CD8+ markers on surface. Promote apoptosis of infected cells by directly injecting proapoptotic chemicals into the cell. Repond to antigens on MHC-I molecules, which present endogenous antigens, so T_c cells are most effective against viral infections
Suppressor/regulatory T-cells
Exrpress CD4+ by also Foxp3. Function by toning down the immune response once an infection has been adequately attacked. These cells turn off automatically to prevent autoimmune disease
Degranulation of Mast Cells leads to ____
The release of histamines
Agglutination
Antibodies sometimes cause this formation of large insoluble complexes that can be phagocytized.
Roles of dendritic cells in both innate and adaptive immunity
Innate: antigen-presenting cells in the skin
Triggers the adaptive response by signaling the proper T and B cells. The T cells, specifically are helper T cells and release interferon-gamma, which activates macrophages and increases their ability to kill bacteria
Interferons
Cytokines released by virally infected cells that decrease the likelihood of neighboring cells becoming affected. Neighboring cells’ membranes decrease in permeability, experience reduced rates of translation and transcription, the body as a whole experiences symptoms due to the interferons, like fever, malaise, aches, etc.)
Mechanism of CD8+ T-cells
They recognize the MHC-I/antigen complex presented on the surface of infected cells and then directly inject proapoptotic chemicals into the cell, killing it before it can spread its virus to neighboring cells in the form of virions.
What is the body’s immune response to viruses that downregulate MHC-I?
NK cells (as part of the innate response) realize this unusual downregulation and consequently trigger apoptosis
Self-antigens
Proteins present on the surface of cells in the body that signal the cell is healthy and normal.
Autoimmunity
Disorder of the immune system that occurs when immune cells attack self-antigens.
“Education” of immature T and B cells
Referring to the elimination of immature T and B cells in the thymus and bone marrow (respectively) that attack self-antigens. This process prevent autoimmune disorders, although it does sometimes fail.
Active immunity
The type of immunity achieved by vaccination. Presentation of a weakened form of the pathogen causes the body to produce antibodies and memory cells against it so that the immune cells can mount a response more quickly in the event of natural exposure to the pathogen.
Passive immunity
Achieved by transferring antibodies to a different individual
Lymph nodes
Small bean-shaped structures along the lymph vessels that contain a lymph vessel, and artery, and a vein. The provide a space for immune cells to be exposed to possible pathogens
Thoracic duct (what is it and where does it lead)
Large lymph duct that most lymph vessels lead to. Located in the posterior chest. Then delivers lymph to the subclavian vein near the heart
Functions of the Lymphatic system
Drainage of the excess fluid left in tissues (due to decreased hydrostatic pressure and the venous ends of capillary beds). Also transports fats in the form of chylomicrons from the GI tract into the bloodstream via lacteals.
Lacteals
Small lymphatic vessels located at the center of each villus in the small intestine
Chyle
Milky white lymphatic fluid that is filled with chylomicrons
Germinal centers
Collections of lymph nodes where B-cells can interact and mature
Clonal selection
Activation of only the T-cells that bear the correct receptors for a specific antigen
Intracellular vs Extracellular Disgestion
Intracellular: involves the oxidation of glucose and fatty acids for energy
Extraceullular: extraction of said nutrients from the food in the GI tract
Alimentary canal
Lumen of the digestive tract that runs from the mouth to the anus. It is technically “outside” the body because it directly ineteracts with the outside world
Order of structures in the GI tract, and the accessories
Order: mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus, rectum
Accessories: salivary glands, pancreas, liver
Enteric nervous system
Neurons that govern the function of the digestive tract, stimulating peristalsis to move food through. Functions independently from the brain and spinal cord
Mastication
Chewing. Increases the surface area to volume ratio so that enzymes can effectively target as much food as possible
Innervation of the salivary glands
by the parasympatheic NS
Enzymes of saliva
Salivary amylase: hydrolyzes starches into smaller sugars (AKA ptyalin)
Lipase: hydrolyzes lipids
Structure of the esophagus
The top third is skeletal muscle and innervated by the somatic NS (voluntary), the bottom third is smooth muscle and innervated by the enteric system (involuntary), and the middle third is a mix of both.
Swallowing the bolus into the esophagus happens through the upper esophageal sphincter. The bolus exits into the stomach through the lower esophageal (cardiac) sphincter
Four anatomical regions, curves, and lining of the stomach
Fundus and body (contain gastric glands), and antrum and pylorus (contain pyloric glands).
Lesser curvature refers to the interior curve. Greater curvature refers to the external curve.
Lining: Rugae
Gastric glands (what are they and name the 3 cell types)
Def: Innervated by the vagus nerve (parasymp NS), respond to signals of sight, taste, and smell of food.
Cells types: mucous, chief, and parietal
Chief cells in the stomach
Secrete pepsinogen (the zymogen form of pepsin) for protein breakdown
Parietal cells
In the stomach. Release HCl to cleave pepsinogen into pepsin. Also secrete intrinsic factor.
Pepsin
Cleaved from pepsinogen by H+ ions secreted by parietal cells. Mechanism involves cleavage of peptide bonds near aromatic amino acids.
Intrinsic factor
A glycoprotein that helps proper absorption of vitamin B12
Pyloric glands (in stomach)
Contain G-cells that secrete gastrin, which induces parietal cells in the stomach to secrete more HCl and signals stomach contractions
Chyme
The semifluid result of the stomach’s enzymes and contractions on the food that was ingested.
The small intestine
3 parts: duodenum, jejunum, and ileum
Main function is chemical digestion, with some minor absorption in the jejunem and ileum
Duodenum
First portion of the small intestine. Food enters it through the pyloric sphincter. Releases enteropeptidase and brush-border enzymes: maltase, isomaltase, lactase, sucrase and peptidases. Also secretes hormones like secretin and cholecystokinin (CCK) into the bloodstream
Brush-border enzymes
Present on luminal surface of cell surface lining the duodenum. Break down dimers and trimers of biomolecules into absorbable monomers
Aminopeptidase
Found in the duodenum. Removes the N-terminal amino acid from a peptide
Enteropeptidase
Activates trypsinogen to trypsin. Also activates procarboxypeptidases A and B
Secretin
Peptide hormone that causes pancreatic enzymes to be released into the duodenum. Regulates the pH of the GI tract by regulating HCl secretion. An enterogastrone: a hormone that slows motility through digestive tract to increase time of chyme exposed to enzymes
CCK
Released from the duodenum in response to the entrance of chyme. Function is to stimulate the release of both bile and pancreatic juices
Bile salts
Amphipathic molecules that aid in mechanical digestions - helps emulsify fats and cholesterol into micelles –> makes them available to pancreatic lipase
Endocrine vs Exocrine cells of the Pancreas
Endocrine: Islets of Langerhans
Exocrine: Acinar cells (produce pancreatic juices)
Pancreatic amylase
Breaks down large polysaccharides into smaller ones
The pancreatic peptidases
Trypsinogen, chymotrypsinogen, and carboxypeptidases A and B (all get activated into their functional forms by enteropeptidase)
Pancreatic lipase
Breaks down fats into free fatty acids and glycerol
Major and minor duodenal papillae
Ducts through which the pancreas’ acinar cells secrete their products into the duodenum
Bile ducts
Connect the liver to the gallbladder (for storage) and the small intestine (for secretion).
Hepatic portal vein
Delivers blood to the liver from the abdominal portion of the digestive tract because it is nutrient-rich and can be processed by the liver before draining into the inferior vena cava on its way to the heart.
Functions of the liver
Detoxification of certain endogenous and exogenous compounds. Activates some drugs. Bile production. Processing of nutrients, and some storage. Synthesis of certain proteins like albumin and clotting factors.
Components of bile
Bile salts, cholesterol, and pigments
Bilirubin
The major pigment of bile. Byproduct of the breakdown of hemoglobin. Get attached the a protein in the liver and then secreted into bile for excretion
Jaundice
Yellowing of the skin that occurs when the liver is unable to excrete bilirubin
Proteins produced by the liver (and their functions)
Albumin: maintains oncotic pressure in the blood and carries many drugs and hormones
Clotting factors: blood coagulation
Cirrhosis of the Liver
Scarring of the liver. Results in portal HTN/backup of fluid which can result in vomiting blood from the burst blood vessels. Hinders clotting factor production and the body’s ability to discard ammonia. Can also lead to carcinoma
Gallbladder
Stores and concentrates bile. Pushes bile out into the biliary tree in response to the release of CCK
Mode of transport of simple sugars and amino acids from the lumen of the small intestine
Secondary active transport and facilitated diffusion
Transport of fatty acids from lumen of small intestine into cells
Short-chain fatty acids: diffusion into epithelial cells and then transport to liver through the hepatic portal circulation
Long-chain fatty acids, cholesterol, and triacylglycerides: get packaged into chylomicrons which then enter the lymphatic system via lacteals
Mechanism of water intake in the small intestine
As solutes are absorbed, water is motivated to move with them out of the lumen to maintain proper osmolarity. Water moves transcellularly ( across cell mem) and paracellularly (squeezing between the cells) to reach the blood
Main function of the large intestine and its three major sections
Function: water absorption
Sections: cecum, colon, rectum
Cecum
First part of the large intestine. Accepts fluid from the small instestine through the ileocecal valce. Also the sight of attachment of the appendix
Colon
Four sections: ascending, transverse, descending, and sigmoid colons. Main function is to absorb water and salts to dehydrate the remaining material to feces.
Internal vs external sphincters of the anus
Internal is under involuntary autonomic control
External is under somatic control
Bacteria in the large intestine produce_____
Vitamin K, which is essential for the production of clotting factor and biotin
Renal Hilum
A deep slit in the center of the medial surface of each kidney. Spans the width of the renal pelvis. Renal artery, vein, and ureter exit through this.
Flow of blood in the kindeys
Renal artery - Afferent arterioles - Glomeruli - Efferent arterioles - vasa rectra (around the Loop of Henle) - venules - Renal vein
Order of structures in the nephron
Bowman’s capsule - proximal convoluted tubule - descending then ascending limbs of the loop of Henle - distal convoluted tubule - collecting duct
Detrusor muscle
Type of muscle that lines the bladder
Sphincters of the urethra
Internal: smooth muscle, involuntary
External: skeletal muscle, voluntary
Describe the innervation of the bladder and what causes excretion
The bladder is innervated by the autonomic NS. Parasympathetic neurons are activated by stretch receptors telling the brain that the bladder is full -> causes the bladder to contract, inducing a shape change that also causes the internal sphincter to contract. The person then has the conscious choice whether to relax the external sphincter.
Pressure difference between Glomerulus and Bowman’s Space
Hydrostatic pressure in the glomeruli is higher than the oncotic pressure that is drawing water out of Bowman’s Space, so there is net filtration
Does glucose diffuse out the glomeruli into Bowman’s space?
YES - although most of it is reabsorbed into the body later in the urinary tract.
Volume of blood filtered by the kidneys per day
180 L
Secretion in the kidney
Movement of solutes from the blood to the filtrate anywhere besides Bowman’s Space. Regulates levels of ions in the blood and helps remove molecules that were too big for filtration through the glomerular pores
Proximal convoluted tubule
Site of major Na+ reabsorption. Filtrate is isotonic to the interstitium because a lot of other solutes and water move. Secretion of H+, K+, ammonia, and urea into the nephron from the interstitium. Reabsorption of amino acids, glucose, and vitamins occurs here
Descending limb of the Loop on Henle
Permeable only to water. Dives deep into the renal medulla, the osmolarity of which gets higher and higher it goes inwards (as the loop travels down). More and more water is reabsorbed as the bottom of the loop is approached.
Countercurrent multiplier system
Flow of filtrate through the loop of Henle is in the opposite direction from the flow of blood through the vasa recta, allowing for maximum reabsorption of water because this way, the filtrate is constantly exposed to hypertonic blood
Ascending limb of the Loop of Henle
Permeable only to salts. Maximizes reabsorption of salts by taking advantage of the increasing medullary osmolarity. As the concentration of salts in the interstitium decreases and the filtrate is traveling up the loop, more and more salts will flow out of the loop and into the interstitium for return to the bloodstream via the vasa recta
Diluting segment
The portion of the ascending loop at the transition from the inner to outer medulla. Characterized by larger cells lining the tubule that hava lot of mitochondria –> faciltate active transport of Na+ and Cl- out of the filtrate. The only portion of the nephron that can create urine that is more dilute than the blood
Compare volume and tonicity of the filtrate at the beginning and end of the loop of Henle
Beginning: the filtrate is isotonic to the blood
End: filtrate is slightly diluted compared to the blood
MAJOR change: volume of the filtrate has significantly decreased, indicating great reabsorption of water
Distal convoluted tubule
Subject to regulation by aldosterone, which promotes Na+ reabsorption. Water follows Na+ back into the body, too, so this concentrates the filtrate. DCT is also a site of secretion of waste from the body
Collecting duct
Site of most water reabsorption –> determines the concentration of the urine. Permeability here is controlled by aldosterone and ADH. Increased permeability means that more water is reabsorbed, concentrating the urine (occurs due to high levels of ADH / aldosterone.
Where is glucose reabsorbed from the filtrate in the kidney?
PCT, along with amino acids, Na+, and vitamins
Juxtaglomerular cells
Release renin when stimulated by low blood pressure
Effect of ACE inhibitors
Prevent the conversion of angiotensin I to angiotensin II, which is supposed to directly promote release of aldosterone from the adrenal cortex. Therefore, aldosterone is not released so blood pressure remains low or is prevented from getting too high
Aldosterone
A steroid hormone produced in the adrenal CORTEX that alters the abilities of the DCT and collecting duct to reabsorb sodium (which motivates water to flow with it
Vasopressin / ADH
A peptide hormone synthesized by the hypothalamus and excreted by the posterior pituitary in response to increased blood osmolarity –> acts to change permeability of the collecting duct to take reabsorb more water to dilute the blood back to normal
Blood pressure regulation by the kidneys
Vasoconstriction by the afferent arteriole will decrease blood pressure in the glomeruli, which stimulates the release of renin, leading to aldosterone-release to help increase reabsorption of Na+ (and effectively, water). Retention of water increases blood pressure.
Vasodilation of the afferent arteriole follows this pathway to decrease blood pressure by NOT stimulating release of renin
Response of the kidneys to increased blood pH
Increase reabsorption of H+ and increase excretion of HCO3-
The three layers of the skin
Going from deepest to surface:
hypodermis, dermin, epidermis
Stratum basale
The deepest layer of the epidermis (which is the surface of the skin). Contains stem cells and is responsible for the proliferation of keratinocytes, which predominately make up the skin and produce keratin
Stratum spinosum
Second deepest layer of the epidermis. Cells are connected to each other. The site of Langerhans cells (macrophages specific to the skin)
Stratum granulosum
Middle layer of the epidermis (third from the top). Site of keratinocyte death and loss of nuclei
Statum lucidum
Only present in thick, hairless skin like on the soles of feet or on palms
Stratum corneum
Outermost layer of the epidermis. Has several dozen layers of flattened keratinocytes, forming a barrier against pathogens and prevents loss of fluids and salt. Contains openings for sweat and sebaceous glands
Layers of the epidermis
Thinl: Come, Let’s Get Sun Burned
Stratum corneum, stratum, lucidum, stratum granulosum, stratum spinosum, stratum basale
Sebaceous glands
Secrete an oily substance (sebum) into hair follicles that lubricates the skin
Melanocytes
Melanin-producing cells in the stratum basale.
Dermis
Middle layer of the skin under the epidermis and above the hypodermis. Site of origins of sweat glands, blood vessels, and hair follicles. Also contains several sensory receptors. Upper sublayer of this section is the papillary layer and beneath it is the reticular layer.
Sensory receptors: Merkel cells (pressure and texture sensations), Meissner’s corpuscles (light touch), Ruffini endings (stretch), Pacinian corpuscles (pressure and vibration)
Hypodermis
Lowest layer of the skin. Contains fat and fibrous tissue
Thermoregulation by the skin
Sweating: postganglionic cholinergic sympathetic neurons (special!) innervate sweat glands and trigger secretion when body temp is high. Cooling occurs due to evaporation of sweat from the skin
Piloerection: arrector pili muscles in the skin contract, causing hair to stand up, which helps trap a layer of heated air near the skin.
Shivering: converts ATP into mechanical and thermal energy, warming the body
Insulation: white fat and, more common in infants, brown fat which has much less efficient electron transport meaning that more heat energy is released as fuel is burned
Where is Na+ reabsorption active in the nephron?
PCT, thick portion of the ascending loop, DCT.
It is passive in the thin portion of the ascending loop because [Na+] is so high by the time the urine reaches the bottom of the loop after descending
Red fibers of skeletal muscle
Slow-twitch. Relatively high myoglobin content and function aerobically. Have a lot of mitochondria for oxidative phosphorylation. Predominant in muscle that must sustain contraction, like those responsible for contraction
White muscle fibers
Fast-twitch. Lower myoglobin and relatively fewer mitochondria. Dominant in muscles that contract quickly but also fatigue quickly
Nucleation of each of the muscle types
Skeletal: multinucleate
Smooth: uninucleate
Cardiac: primarily uninucleate, although some are dinucleate
Intercalated discs
Structures that connect cardiomyocytes and have many gap junctions that allow the transfer of ions between cells, allowing for simultaneous depolarization of neighboring cells
Myogenic activity
Contraction of muscle without input from the nervous system. Smooth and cardiac muscle cells are capable of this
Effect of epinephrine on the heart
Binds to adrenergic receptors on the cardiac muscle cells and triggers a cascade that increases Ca2+ concentration in the cells, which increases contraction
Titin
Protein in the sarcomere that anchors actin and myosin together, thus preventing excessive stretching
Parts of the Sarcomere (ie all of the lines, bands, and zones)
Z-line: the boundary of the sarcomere
M-line: middle of the sarcomere that runs down the middle of the thick filaments
I-band: region containing only thin filaments
H-zone: contains only thick filaments
A-band: contains thick filaments in its entirety (the only one of these zones that remains constant in length throughout contraction)
Myofibrils
Skeletal muscle cell structures of sarcomeres attached end-to-end. Surrounded by the sarcoplasmic reticulum
Sarcoplasmic Reticulum
A modified ER than encases the myofibrils and contains a high [Ca2+]
Sarcoplasm
Modified cytoplasm in skeletal muscle cells
Sarcolemma
Cell membrane of a myocyte. Able to distribute action potentials across entire cell using T-tubules
Muscle fiber
Another name for a skeletal muscle cell. Contains many myofibrils in parallel
The role of Ca2+ in skeletal muscle contraction
Depolarization from T-tubules reaches the sarcoplasmic reticulum, releasing Ca2+ into the cell. Ca2+ binds to troponin which induces a conformational change in tropomyosin, effectively exposing the myosin-binding site
Steps of the cross-bridge cycle
Myosin binding site is already exposed and myosin is carrying ADP+P_i. Rapidly successive release of ADP and P_i provides energy for the power stroke which pulls the actin over the myosin, shortening the sarcomere. New ATP then binds to myosin, decreasing its affinity for actin, so it unbinds. This ATP is then partially hydrolyzed, which recocks the myosin head back into place for another cycle
Mechanism of relaxation
ACh is decreased in the NMJ by acetylcholinesterase, allowing the sarcolemma to repolarize, leading to a decrease in Ca2+ release. SR also takes up Ca2+. This causes tropomyosin to re-cover the myosin-binding sites on actin and the sarcomere is allowed to re-lengthen
Tonus
Constant low-level contraction, present in blood vessels
Latent period
Time between reaching threshold for contraction and the onset of contraction. During this time, action potentials are traveling over T tubules to the SR and Ca2+ is released from there.
Tetanus (as the physiological phenomenon)
Muscles are exposed to such frequent and prolonged stimulation that they are unable to relax. Results in muscle fatigue. Occurs in the disease tetanus and, to a lesser degree, under normal conditions, too.
Creatine phosphate
One of the energy reserves in skeletal muscle cells. “Stores” ATP through the following reaction
creatine + ATP <=> creatine phosphate + ADP
creatine phosphate undergoes dephosphorylation to produce ATP when the cell needs it
Oxygen debt
The difference between the amount of O2 needed by the muscle cell and the amount actually present. Myoglobin helps minimize this by storing O2 through high-affinity binding and then releasing it during times of extreme exercise.
Myglobin
One of skeletal muscle cells’ energy stores. Binds with high affinity to O2 to hold in reserve to be able to keep aerobic respiration going when O2 is running low.
Shift in the myoglobin-O2 binding curve during exercise
Rightward shift, indicating decreased affinity of myoglobin for oxygen. This allows unloading of the O2 so that the muscle cell can use it in aerobic respiration
From which germ layer is bone derived?
Embryonic mesoderm
Cancellous bone
Spongy bone. The inside contains bony points called trabeculae surrounded by bone marrow. In the core of bones
Segments of long bones
Diaphyses (the shafts) swell at each end into the metaphyses, which terminate into epiphyses
Red bone marrow
Filled with hematopoietic stem cells that give rise to blood cells
Yellow bone marrow
Composed of fat and is relatively inactive
Epiphyseal plate
AKA growth plates. Located at the internal edge of each epiphysis. During puberty, they are filled with mitotic cells and contribute to growth until the plates close
Periosteum
Protective sheath around long bones, the cells of which are capable of differentiating into bone-forming cells. Essential for bone growth and repair
Bony matrix and osteons
Osteons are the structural units of the bony matrix and allow for even distribution of organic and inorganic materials. Each osteon is laid out in concentric circles known as lamellae, surrounding a central microscope channel, which contain blood vessels, nerve fibers, and lymph vessels
Lacunae
The spaces int eh bony matrix between lamellae. They house osteocytes. Interconnected with each other by canaliculi in order to exchange nutrients and wastes between the osteocytes and both types of canals
Osteoblasts
Build new bone
Osteoclasts
Macrophages present in bone that cause breakdown of old bone, thus releasing the Ca2+ and phosphate into the bloodstream
Parathyroid hormone
Responds to low Ca2+ levels in the blood by triggering bone resorption, thus increasing Ca2+ and phosphate levels in the blood
Vitamin D
Activated by parathyroid hormone. Promotes bone resorption, thus recycling old bone to allow formation of new, healthier bone
Calcitonin
Response to high levels of Ca2+ in the blood and triggers bone formation, thus lowering Ca2+ in the blood
Chondrin and Chondrocytes
Chondrin is the firm but elastic matrix that makes up cartilage. It is secreted by cells called chondrocytes
Endochondral ossification
Hardening of cartilage into bone. Responsible for formation of most long bones in the human body
Intramembranous ossification
Undifferentiated embryonic connective tissue (mesenchymal tissue) is transformed into and replaced by bone. This is how the bones of the skull are formed
Synovial fluid
Lubricates the joint. Secreted by the synovium into the joint/articular cavity
Origin and insertion
Origin: the end of a muscle that has the larger attachment to bone, usually proximal
Insertion: the end of the muscle that has the smaller attachment to bone, usually distal
Which chemical forms most of the inorganic components of bone?
Hydroxyapatite crystals
Locus
Location of a gene on a chromosome. Each gene has a particular one
Penetrance
The proportion of individuals in a group carrying a certain allele and actually express the phenotype
Expressivity
Describes varying phenotypes despite identical genotypes
Mendel’s second Law of Independent Assortment
Inheritance of one genotype does not affect the inheritance of another
In which phase of meiosis does recombination occur?
Prophase I
Transforming principle
Bacteria can increase genetic variability by sharing genes with members of their species in close proximity. Discovered by Griffith
Transposons
Elements that can freely insert and remove themselves from a genome. They can disrupt a gene is they attach in the middle of one
Chromosome-level mutations are ____-scale ompared to nucleotide-level mutaitons
large
Translocation mutation
When a segment of DNA from one chromosome is swapped with a segment of DNA from another chromosome
Inborn errors of metabolism
Defcts in genes required for metabolism
Genetic Leakage
Flow of genes between species. Sometimes to produce hybrid offspring like mules
Genetic drift
Changes in the gene pool of a species due to chance. Causes a reduction in genetic variability
Inbreeding depression
Overall reduced fitness of the population due to inbreeding and consequent decrease in genetic variation
Recombination frequency
The likelihood that two alleles are separated from each other during recombination. Tightly linked genes have recombination frequencies near 0 percent, whereas weakly linked genes have RFs near 50%. Analysis of these values allows us to create a genetic map
Conditions of Hardy-Weinberg Equilibrium
All five must be met to achieve a stable gene pool and NO evolution:
- Population is very large (no gen. drift)
- There are no mutations in the gene pool
- Mating between individuals is the population is random (no sexual selection)
- There is no migration of individuals into or out of the population
- The genes in the population are equally successful at being reproduced
Hardy-Weinberg equations
p+q = 1
p^2 + 2pq + q^2 = 1
p: the frequency of the dominant allele
q: the frequency of the recessive allele
Rate of occurence of the dominant phenotype (H-W equation)
p^2 + 2pq
Inclusive fitness
A measure of an organism’s success in the population, based on the number of offspring, the ability to support the offspring, and then the ability of the offspring to support others
Punctuated equilibrium
Theory of evolution that was theorized by studying the fossil record. It supports the idea that species would be relatively stagnant and not evolving over long periods of time and then go through short bursts of evolution
Modes of natural selection
Stabilizing selection, directional selection, and disruptive selection
Stabilizing selection
Keeps phenotypes within a certain range by selecting against extremes. Ex: birthweight remains in a narrow range because either extreme can be dangerous
Directional selection
Emergence and dominance of an initially extreme phenotype
Disruptive selection
Two extreme, distinct phenotypes are selected over the norm. These distinct phenotypes are known as polymorphisms
Polymorphisms
Naturally occurring differences in the form between members of the same population. Ex: light and dark coloration of butterflies in the same species
Adaptive radiation
Concept that describes the rapid rise of a number of different species from a common ancestor. It is promoted by rapid environmental changes or isolation of small groups of the ancestral species
Niche
An environment (encompassing habitat, resources, and predators) for which a certain species is adapted to survive in
Prezygotic reproductive isolation
Mating between species is no longer possible due to evolution. Zygote cannot even form
Postzygotic reproductive isolation
Allows gamete fusion, but the zygote is not stable or viable enough to survive. Two groups can no longer mate with each other due to speciation apart
Molecular clock model
The degree of genomic similarity correlates with the amount of time since two species split off from the same common ancestor
Where are post-transcriptional modifications carried out?
What about post-translational?
P-transcrip: In the nucleus
P-transl: A couple of locations are possible including the cytoplasm, ER, and Golgi
Euploidy
Having one or more complete sets of chromosomes
Tissue with the highest number of glucagon receptors
Liver.
NOT skeletal muscles because the primary function of glucagon is to increase blood glucose levels, and skeletal muscles’ glycogen stores are not broken down for release into the bloodstream, rather, the muscles use the glucose themselves
Endosome
A collection of intracellular sorting organelles
In beta-oxidation, which carbons wind up in which products?
C1 and C2 wind up in the acetyl-CoA (the two-carbon molecule)
C3 (and above) wind up on the acyl CoA - the remaining fatty acid chain
Describe the effect on SDS-PAGE of a protein having an abundance of negative charged residues in its peptide chain prior to SDS denaturation
Many negativeley charge residues will result in SDS-PAGE producing an estimate of the protein’s weight that is less than the actual value because the the negative charge induced by SDS plus the existing negative charge intensifies the charge so much that the protein will travel further in the gel towards the positive end (indicating smaller size) than what is accurate
Passive Immunity
The transfer of active humoral immunit in the form of ready-made antibodies, from one individual to another.
Ex: diffusion of antibodies from mother to fetus through the placenta
Contrast Anaphase I and Anaphase II of Meiosis
What are the resulting ploidies of meiosis I vs II?
Anaphase I: Separation of homologous chromosomes
Anaphase II: Separation of sister chromatids
Cells after meiosis I: 2 haploid cells, 2 sister chromatids of each chromosome
After meiosis II: 4 haploid cells, 1 sister chromatid of each chromosome
Autosomal genes
Genes that are NOT located on X or Y chromosomes. They are expressed to the same extent in males and females
Males tend to exhibit X-linked disorders ____ frequently than females in the population because…
more; they only have one X chromosome, so the “dominant” X allele has to be the one that is on there (the single allele), in contrast to females who can have an abnormality on one X chromosome be canceled out by a normal allele on their other X chromosome
In short: males only have one allele for x-linked genes so they would have to express it
Genes that are located close to each other on a chromosome have a _____ chance of being separated in recombination
Low
Parallel evolution
Describes when two closely related species (with a common ancestor) develop similar characteristics due to a similar environment
Divergent evolution
Describes the evolution of two species descended from a common ancestor, but now inhabit distinct environments, so have now developed different characteristics
T/F: Genes that are rarely expressed are likely found on Euchromatin
False - genes that are located on the loosely wrapped euchromatin are more available for transcription machinery to access them, so it makes more sense for low-expression genes to be located in the more tightly coiled heterochromatin
Describe the use of Hybridization to detect gene expression
Determine whether there is a specific mRNA of interest by incubating cytosol from the cell of interest with a fluorescently labeled complementary RNA. The degree of fluorescence after washing away the unbound mRNAs shows the degree of hybridization, which can be used to determine the amount of mRNA of interest present in the cytosol sample.
DNA Mismatch Repair Machinery (def and mechanism)
Corrects mismatched bases in DNA strands during replication - does NOT repair RNA.
Mechanism: Upon detection of a mismatched base, a nuclease enzyme cuts out the erroneous nucleotide and a couple of its neighboring nucleotides, and then repairs the sequence with DNA polymerase. DNA ligase seals the nicks
Synapsis
During prophase I of meiosis when homologous chromosomes recognize each other and line up side by side to form a tetrad. Allows cross over to occur, thus increasing genetic diversity
Epitope and bond-type
The antibody binding region on an antigen. Antibody binds noncovalently
Ubiquitin tags
Label proteins for destruction by flagging them to be sent to the proteasome
Lysosome vs Proteasome
Lysosome degrades secretory proteins that entered the cell via endocytosis, whereas proteasome degrades cytosolic proteins that were sent to it due to ubiquination
k_cat
Turnover number of an enzyme. Equal to the number of substrate molecules converted to product per second under saturating conditions
Slope of a Lineweaver-Burke plot
Km/Vmax
Effect of Urea on Proteins
Urea denatures the proteins by exposing hydrophobic groups and interfering with H-bonding in the amino acid backbone.
Increases unfolding
Average weight of a single Amino Acid
110 Da
How is the tertiary structure of a protein stabilized?
Via noncovalent interactions between amino acid sidechains
ONE EXCEPTION: disulfide bonds (covalent) can occur between Cys sidechains, require an oxidizing environment (cannot happen in the cytosol because it is a reducing environment)
Ternary complex
A group of 3 bound molecules with at least one of them being a protein
May either bind in a specific order or random
Native PAGE
Takes place in a gel that is free of any detergents or reducing agest, which means that the native structure of the protein is retained
Succinate-Ubiquinone Reductase
Complex II of the ETC, also called succinate dehydrogenase. An oxidoreductase that moves electrons from succinate to Complex III.
The first e carrier in Complex II is FADH2, and then the carrier that takes the e to Complex III is ubiquinone (reduced to ubiquinol).
As the ETC progresses, the reduction potentials of the electron carriers gets _________.
Higher!
Stereospecific reactions of the Citric Acid Cycle
Formation of D-isocitrate via Aconitase
Formation of L-malate via fumarase
Fructose -2.6-bisphosphate
Synthesis of this enzyme is triggered by insulin - it then activates PFK-1 –> driving glycolysis.
Also inhibits gluconeogenesis by allosterically inhibiting the catalytic activity of F1,6BP
Increases net catabolism of glucose
Innervation of the adrenal medulla
ONLY innervated by the sympathetic nervous system
Respective cellular locations of fatty acid oxidation and synthesis
Oxidation: mitochondria (primarily - note that longer chains must start out in the peroxisome)
Synthesis: cytosol
Chaperones
Proteins that facilitate proper folding and prevent aggregation
Signal sequences
Portions of mature mRNA located in the 5’ region. They signal the ribosome that translation needs to finish occurring at the location of the Rough ER
Full name of NADH
Nicotinamide adenine dinucleotide + hydrogen
Endomembrane system
The portion of the cell that is responsible for modifying proteins that will be secreted (e.g. cleavage of insulin into its mature form)
Major Histocompatibility Complex
Group of genes that encode for proteins involved in immune system’s ability to recognize the self
Increased levels of which hormone indicate increased levels of stress?
Cortisol
Quorum Sensing
The ability of cells to detect and respond to cell population density by appropriate regulation of genes
Functions of Liver Cells
- Regulation of blood glucose via glycogenolysis, glycogenesis, and gluconeogenesis
- Storage of glycogen, minerals (iron), and vitamins
- Synthesis of macros like plasma proteins (albumin, clotting factors), fats, ketone bodies, and cholesterol
- Production and secretion of bile
- Breakdown/detoxification of numerous drugs and metabolic waste products
Nuclear Localization Sequence
Short sequence of amino acids that mediates transport of the protein from the cytoplasm into the nucleus
Cell type that lines Bowman’s Capsule
Simple squamous epithelial
