Bio/Biochem II Flashcards
anterior pituitary hormones
FSH, LH, TSH, STH, ACTH, GH, and prolactin Anterior Pituitary Hormones”FLAGTOP” F: Follicle Stimulating Hormone L: Luteinizing Hormone A: ACTH G: Growth Hormone T: Thyroid Stimulating Hormone O: MSH - melanOcyte stimulating hormone P: Prolactin
posterior pituitary hormones
ADH (vasopressin) and oxytocin
only parathyroid hormone is: parathyroid hormone
A hormone of the parathyroid gland that regulates the metabolism of calcium and phosphorus in the body.
thyroid hormones
T3, T4, calcitonin
adrenal cortex hormones
aldosterone and cortisol
adrenal medulla hormones
catecholamines (epinephrine and norepinephrine)
Pancreas hormones
insulin, glucagon, somatostatin (inhibits digestive hormones, slows digestion)
reproductive organ hormones
estrogen, testosterone, progesterone, human chorionic gonadotropin (hCG)-Human chorionic gonadotropin (hCG) is a hormone produced by the placenta after implantation.
keratin is
an intermediate filament
actin and ______ are the same thing
microfilaments
negatively charged forms of asparagine and glutamine
asparatate and glutamate
a mother’s breastmilk transfers this immune protection to the infant:
igG antibodies
Gastrulation
the process in which a gastrula develops from a blastula by the inward migration of cells aka the process whereby the inner cell mass is converted into the trilaminar embryonic disk comprised of the three primary germ layers (ectoderm, mesoderm, and endoderm)
Ectoderm
outermost germ layer; produces sense organs, nerves, and outer layer of skin
Endoderm
innermost germ layer; develops into the linings of the digestive tract and much of the respiratory system
Mesoderm
middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems
the normal maturation pathway of ova is…
oogonia (2n)->Primary oocyte (occurs via mitosis, 2n) ->secondary oocyte (completion of meiosis 1, n) -> mature ovum (completion of meiosis 2, this process requires sperm (n)) each month one primary oocyte comes out of its arrest (in prophase 1) and develops into a secondary oocyte, which ruptures from the follicle and is released into the fallopian tube
mullerian ducts->differentiate to form
fallopian tubes, uterus, uterine cervix, and the superior aspect of the vagina
mneumonic for the path taken by spermatozoa is SEVEN UP
Seminiferous tubules Epididymis Vas deferens Ejaculatory ducts nothing (placeholder for N to make mneumonic work) Urethra Penis
Where do sperm mature after spermatids are generated?
epididymis
trophoblast
outer cells of the blastocyst that secrete enzymes that allow implantation, eventually grow to generate the placenta
Morula
A solid ball of cells that makes up an embryo; in humans, this stage occurs within four days of fertilization.
Blastocyst
A fluid-filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. This is the structure that implants in the endometrium of the uterus.
in males the ______ duct develops into the male reproductive organs
Wolffian
the ___ gene on the _____ chromosome causes the development of testes
SRY, Y
During labor, the hormone _____ is released to initiate contractions. The contractions that occur stimulate the release of more oxytocin which relaxes the cervix and allows the baby’s head to descend. This response is an example of:
oxytocin, positive feedback
In SDS-PAGE, SDS (i.e. lauryl sulfate) is an anionic detergent, meaning that when dissolved its molecules have a net negative charge. SDS denatures and coats proteins to give them a uniform negative charge, causing them to migrate towards the _________
positively-charged anode in the gel
Pepsin
an enzyme released in the stomach that catabolizes proteins to smaller peptides and amino acids
Amylase
an enzyme that catalyzes the hydrolysis of starches to sugars and is produced by the salivary glands and pancreas
Hexokinase
an enzyme that catalyzes the phosphorylation of sugars
Lactase
an enzyme that catalyzes the hydrolysis of lactose to glucose and galactose
ejaculatory pathway
vas deferens, ejaculatory duct, urethra. Glands along this pathway produce semen. Seminal vesicles, prostate gland and bulbourethral gland. Testicular activity is controled by two anterior pituitary hormones. FSH regulates sperm production (ICSH-Interstitial cell stim horm.) LH stimulates the interstitial cells to produce testosterone.
females are born with large numbers of primary oocytes arrested in prophase one, but after puberty ovulation begins to occur where one primary oocyte completes _______ to become ________
meiosis 1, a secondary oocyte -primary oocytes are diploid while secondary oocytes are haploid since homologous chromosomes separate during anaphase of meiosis 1
the menstrual cycle is variable because the _______ phase is variable while the ______ phase is relatively constant
variable= follicular/proliferative phase constant= leuteal/secretory
menopause
the progressive loss of ovarian follicle units known as atresia, results in a decrease in ovarian production of estrogen, this reduces the negative feedback to the anterior pituitary, ultimately increasing levels of LH and FSH
The most common function of proteins in the body is
not enzymatic, but structural. Structural proteins are fibrous proteins that have an elongated shape and provide structural support for cells and organ tissues. The first type of fibrous proteins are keratins, which form the skin, hair, and nails. not enzymatic, but structural. Structural proteins are fibrous proteins that have an elongated shape and provide structural support for cells and organ tissues. The first type of fibrous proteins are keratins, which form the skin, hair, and nails. A third type of structural protein you should know for test day is collagen, which is found in tendons, forms connective ligaments within the body, and gives extra support to the skin.
Keratin
The first type of fibrous proteins are keratins, which form the skin, hair, and nails. Keratins are classified as soft or hard according to their sulfur content (i.e. the relative number of cysteine residues in their polypeptide chains). The low-sulfur keratins of the skin are much more flexible than the high-S, hard keratins.
actin and myosin
The second type of fibrous proteins you must know are the actin and myosin proteins of muscle tissue. Actin and myosin interact to form cross-linkages that allow the sliding of the filaments over each other in muscle contraction, which takes place through the contraction and relaxation of the sarcomere, the fundamental unit of all muscle fibers. When muscle contracts, the actin and myosin filaments slide over each other and the H-zone (myosin-only region), Z-lines (sarcomere boundaries), and I-band (actin-only region) all shrink, while the A-band (the entire myosin region) remains the same size. The opposite occurs upon muscle relaxation.
collagen
A third type of structural protein you should know for test day is collagen, which is found in tendons, forms connective ligaments within the body, and gives extra support to the skin. Collagen is a triple helix formed by three proteins that wrap around one another. Many collagen molecules are cross-linked together in the extracellular space to form collagen fibrils to provide structural support for the cell. Elastin polypeptide chains are cross-linked together to form flexible, elastic fibers that give stretched tissues flexibility and the ability to recoil spontaneously as soon as the stretching force is relaxed.
Where are endorphins released from?
Endorphins are produced in the anterior pituitary gland, along with other hormones such as luteinizing hormone (LH), follicle stimulating hormone (FSH), and growth hormone (GH).
What are depressants?
Depressants cause relaxation by reducing nervous system activity. Alcohol is the most commonly used depressant. It works by stimulating the production of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter associated with reduced anxiety, and dopamine, which promotes euphoria. Alcohol slows the activity of the frontal lobe, reducing judgment and lowering inhibitions. While drinking, people can become unable to recognize the consequences of their actions, and their speech may be slurred and motor skills diminished.
WHat are opiates?
Opiates are derived from the poppy plant and include such drugs as morphine and codeine. Opiates cause a sense of euphoria and a decreased reaction to pain by binding to opioid receptors in the nervous system. Opiate overdose can cause death when the brain stops sending signals for respiration. After prolonged use, these drugs can cause the brain to entirely stop producing endorphins, meaning that withdrawal is very painful.
What are stimulants?
Stimulants increase arousal in the nervous system, often through the release and inhibition of the reuptake of dopamine, norepinephrine, and serotonin. This effectively increases arousal, increasing heart rate and blood pressure, and creating effects of anxiety, delusions of grandeur, euphoria, hypervigilance, and decreased appetite.
What are hallucinogens?
Hallucinogens, such as lysergic acid diethylamide (LSD) and ketamine, distort perception, enhance sensory experiences, and cause introspection, all while increasing heart rate and blood pressure, increasing body temperature, and dilating the pupils.
Is marijuana a stimulant, depressant, or hallucinogen?
marijuana has qualities of a stimulant, depressant, and hallucinogen. Marijuana, which is the name used for the leaves and flowers of the plants Cannabis sativa and Cannabis indica, has an active chemical called tetrahydrocannabinol (THC) which affects certain receptors in the brain. Additionally, THC increases the production of GABA and dopamine. Physiologically, THC can cause an increase in appetite, dry mouth, fatigue, eye redness, lowered blood pressure, and increased heart rate.
What is the most common excitatory neurostransmitter and what is the most common inhibitory neurotransmitter?
Glutamate is an excitatory neurotransmitter and is the most common, as 90% of brain cells are responsive to glutamate. In contrast, GABA is the main inhibitory neurotransmitter of the CNS, and it hyperpolarizes cells to reduce action potential firing. Alcohol binds and activates GABA receptors (in other words, alcohol is a GABA agonist), so the effects of GABA are associated with alcohol intoxication. Glycine is another inhibitory neurotransmitter found in the spinal cord and brainstem that can work in conjunction with GABA.
limbic system
neural system located below the cerebral hemispheres; associated with emotions and drives
What is innate immunity?
Nonspecific protection against foreign substances indiscriminantly. All cells but lymphocytes. Cells include: Eosinophils are granulocytes, or cells that contain small particles termed granules in their cytoplasm. Other granulocytes include basophils and neutrophils, both of which also are involved in innate immunity. non-cellular component of the innate immune system includes anatomical barriers and signaling molecules such as cytokines and complement proteins, while the cellular component includes a range of white blood cell types (leukocytes) that play various roles in responding to threats. White blood cells include neutrophils, lymphocytes, monocytes (which differentiate into macrophages or dendritic cells), eosinophils, basophils, and mast cells. The various components of the innate immune system can act independently or be coordinated in the process of inflammation.
What is passive immunity?
the short-term immunity that results from the introduction of antibodies from another person or animal.
What is the adaptive immune system?
The adaptive immune system includes B cells and T cells, both of which are lymphocytes that are produced in the bone marrow and mature in the lymphatic system. B cells recognize antigens and secrete large amounts of antibodies in response. The human body utilizes five classes of antibodies: immunoglobulin (Ig) A, IgD, IgE, IgG, and IgM, which differ in the details of their heavy chains. This response is known as humoral immunity. In contrast, T cells correspond to the cell-mediated branch of the adaptive immune system. T cells, which mature in the thymus, recognize cells that were originally self, but have been damaged by viral infections or have malfunctioned in ways likely to turn them into cancer cells. Then, various subgroups of T cells either directly attack compromised/foreign cells or mobilize responses to them based on antigen fragments that are presented by major histocompatibility complex (MHC) class I and II.
In eukaryotes which residues are most prone to phosphorylation?
In eukaryotes, the residues most prone to phosphorylation are serine (S), tyrosine (Y), and threonine (T).
What is the difference between kinases, phoshatases, and phosphorylases?
A kinase functions to add a phosphate group to its substrate. The opposite of this activity is the removal of phosphate from a substrate, a function which is performed by phosphatase enzymes. Phosphorylase enzymes also add phosphate groups to their substrates, so the “general effect” of a phosphorylase on its substrate is similar to that of a kinase. Specifically, kinases transfer phosphate groups from a high-energy source (usually ATP) to their substrates, while phosphorylases transfer phosphate from an inorganic phosphate source.
What are Lyases
group elimination to form double bonds
What are Ligases
catalyze the formation of bonds with the input of ATP and the removal of water
What are the two hormones used for fluid regulation?
Two major hormones respond to low fluid levels by increasing fluid retention: aldosterone (the main example of a class of steroid hormones known as mineralocorticoids) and anti-diuretic hormone (ADH), a peptide hormone that is also known as vasopressin. However, these two hormones have different mechanisms. Aldosterone works by increasing sodium absorption in the distal convoluted tubule and collecting duct of the nephron, which drives water absorption. Aldosterone also increases excretion of potassium and hydrogen ions in the urine. In contrast, ADH increases the permeability of the collecting duct to water, thereby increasing water absorption. Thus, ADH acts to reduce the osmolarity of blood by increasing the amount of water present without changing the solute levels, whereas aldosterone does not affect osmolarity because sodium reabsorption drives water absorption.
What is ANP/ANF?
Two major hormones respond to low fluid levels by increasing fluid retention: aldosterone (the main example of a class of steroid hormones known as mineralocorticoids) and anti-diuretic hormone (ADH), a peptide hormone that is also known as vasopressin. However, these two hormones have different mechanisms. Aldosterone works by increasing sodium absorption in the distal convoluted tubule and collecting duct of the nephron, which drives water absorption. Aldosterone also increases excretion of potassium and hydrogen ions in the urine. In contrast, ADH increases the permeability of the collecting duct to water, thereby increasing water absorption. Thus, ADH acts to reduce the osmolarity of blood by increasing the amount of water present without changing the solute levels, whereas aldosterone does not affect osmolarity because sodium reabsorption drives water absorption.
What are the steps of fertilization?
Fertilization takes place in the Fallopian tube, when a sperm cell encounters a secondary oocyte. The sperm cell passes through the corona radiata, a layer of follicular cells surrounding the oocyte, and the zona pellucida, a layer of glycoproteins between the corona radiata and the oocyte. This triggers the acrosome reaction, in which digestive enzymes are released that allow the nucleus of the sperm cell to enter the egg. The secondary oocyte completes meiosis II, creating a second polar body and a mature ovum. Then, the haploid nuclei of the sperm cell and the ovum merge, creating a diploid one-cell zygote. As the zygote travels to the uterus, it undergoes a series of mitotic cell divisions known as cleavage. Once the zygote has cleaved into a mass of 16 cells by three to four days after fertilization, it is known as the morula. By three to five days after fertilization, the morula develops some degree of internal structure and becomes a blastocyst, with a fluid-filled cavity in the middle known as the blastocoel. The blastocyst implants in the uterine endometrium and further differentiates into the gastrula. The gastrula has three layers: the ectoderm, the mesoderm, and the endoderm. These layers eventually go on to form specific organs and components in the body.
What are the steps of mitosis?
In eukaryotes, the process of asexual cell division is known as mitosis. Mitosis takes place in four phases: prophase, metaphase, anaphase, and telophase. Prophase prepares the cell for mitosis: the DNA condenses such that distinct chromosomes become visible, as sister chromatids (or copies of a given chromosome) join at a region known as the centromere. The kinetochore assembles on the centromere, and is the site where microtubule fibers that extend from the centrosome and form the mitotic spindle attach to pull the sister chromatids apart in later stages of mitosis. Other microtubules known as asters extend from the centrosome to anchor it to the cell membrane. Additionally, the nuclear envelope and the nucleolus disappear, and the mitotic spindle forms. In metaphase, the chromosomes line up at the middle of the cell along an imaginary line that is known as the metaphase plate. In anaphase, the sister chromatids are separated and pulled to opposite sides of the cell by shortening of the microtubules attached to the kinetochores. Telophase can be thought of as the opposite of prophase, as a new nuclear envelope appears around each set of chromosomes and a nucleolus reappears within each of those nuclei. The process of mitosis is completed by cytokinesis.
What is crossing over?
In prophase I of meiosis, homologous chromosomes (i.e., the maternal and paternal copies of a given chromosome) pair up with each other in a process known as synapsis, forming tetrads. While paired up, homologous chromosomes may exchange genetic information in a process known as crossing over. The crossing-over points are known as chiasmata. This process results in recombinant DNA that is another source of variation in sexual reproduction, in addition to the variability inherent to the process. In metaphase I, homologous pairs, which take the form of tetrads, line up at the metaphase plate. The orientation of the homologous pairs is random in terms of which side of the metaphase plate the maternal or paternal copy of a given chromosome in a homologous pair winds up. In anaphase I, the homologous pairs are separated, and one member of each pair is pulled to each side of the cell. In meiosis II, which operates similarly to mitosis, the sister chromatids are split up into two haploid daughter cells.
single v double crossover
-Single-crossover events affect only the ends of chromosome arms, while double-crossover events can affect segments in the middle of chromosome arms. -A double-crossover event is one in which chromosomal arms of homologous chromosomes cross over in two different places along the arm. This results in a section in the middle of each chromosome being exchanged. A simplified schematic of a single- vs. a double-crossover event is shown below.
What are myocytes?
Myocytes are skeletal muscle cells that have multiple nuclei on the periphery of the cell and they are formed via the fusion of multiple precursor cells.
What are the two types of fibers in skeletal muscles?
There are two different types of fibers within skeletal muscles: red fibers (slow-twitch fibers) and white fibers (fast-twitch fibers). Red fibers obtain their color from the presence of abundant reserves of myoglobin, and are also rich in mitochondria. This means that they prefer oxidative metabolism, and therefore are present in large quantities in muscles that specialize in performing less intense actions over a longer period of time. White fibers, in contrast, lack those elements, and tend to mobilize glycogen for quick bursts of intense action followed by fatigue.
What are intercalated disks?
A unique feature of cardiac muscle is that its cells are connected by structures known as intercalated discs, which connect the cytoplasm of adjacent cardiac muscle cells, allowing ions to pass from cell to cell. These connections are known as gap junctions, and they allow action potentials to pass rapidly from one cardiac muscle cell to another.
esterification of fatty acids is synonymous with
the formation of glycogen from glucose; it packs the fatty acids into molecules for storage rather than using them immediately. This would occur if glucose were already abundant in the body.
The mitotic spindle is composed of what?
microtubules
What are analogous structures?
-structures that perform a similar function but are not similar in origin -Analogous structures are those structures that evolved independently to carry out the same function. Thus, the wing of a bee and the wing of a bird are analogous structures.
What are homologous structures?
homologous structures are similar in origin but not function (whale flippers /human arms) Homologous structures are those that have a similar evolutionary history, arising from the same source, even if they now have different functions. The forelimbs of mammals (human arm, walrus flipper, bat wing) would all be homologous despite their different functions.
What is an agonist?
a molecule that, by binding to a receptor site, stimulates a response
What are lacteals?
are structures in the intestines associated with absorbing fat into the lymphatic system.
acetylation of histones
opens chromatin, allowing transcription
What are the eicosanoid signaling molecules?
prostaglandins, thromboxanes, and leukotrienes signaling molecules made from the oxidation of fatty acids \ Eicosanoids may also act as endocrine agents to control the function of distant cells.
What are catecholamines?
dopamine, norepinephrine, epinephrine (all derived from tyrosine)
Lysozyme
enzyme that kills bacteria
Bacterial genes do not have
introns
Meiosis I results in
homologous chromosomes being separated, generating haploid daughter cells Meiosis I results in 2 haploid cells, each with 23 chromosomes consisting of 2 sister chromatids per chromosome. In the male, the sister chromatids are split into 4 gametes during meiosis II. For females, meiosis I results in a secondary oocyte (a gamete) and a polar body. Penetration of the secondary oocyte by a sperm brings on anaphase II. Telophase II produces a zygote and a second polar body. Remember for the MCAT: mitosis results in diploid daughter cells, while meiosis results in haploid cells to produce gametes.
Rt-PCR gives us info on?
the amount of RNA expressed.
What is an apoenzyme?
an inactive enzyme that lacks a necessary cofactor.
What is a coenzyme?
Coenzymes are small organic molecules that bind (or donate functional groups) to coenzyme-dependent enzymes.
What is a cofactor?
a substance (other than the substrate) whose presence is essential for the activity of an enzyme.
What is the purpose of the pulmonary surfacant?
Its adsorption to the water-alveolar interface decreases surface tension, decreasing the pressure difference required to inflate the airway. Pulmonary surfactant adsorbs to the air-water-alveoli interface, reducing surface tension and the total force resisting expansion. This increases pulmonary compliance—a measure of lung volume change at a given pressure of inspired air—and decreases the work required to expand the lungs at a given atmospheric pressure. In general, surfactant molecules are amphipathic, meaning that they contain both hydrophobic and hydrophilic regions. The diagram below shows surfactant molecules surrounding a micelle of oil. The hydrophobic tails of the surfactant molecules mix well with the hydrophobic oil, while the hydrophilic heads point away from the oil droplet.
what amino acid does acetylation happen to?
Lysine-Acetylation promotes transcription by attaching acetyl groups to lysine residues on histones, making them less positively-charged and causing a looser wrapping pattern that allows transcription factors to access the genome more easily.
Uncompetitive v noncompetitive inhibition
In noncompetitive inhibition, the inhibitor can combine with either the enzyme or the enzyme-substrate complex. In pure noncompetitive inhibition, the value of Vmax is decreased. Since these inhibitors do not compete with the substrate, their activity is unaffected by substrate concentration. Since the inhibitor always affects a consistent proportion of the available enzyme, Vmax is reduced. However, Km remains the same since if Vmax, is reduced, Vmax/2 is reduced proportionally, and the amount of substrate required to reach this new, reduced Vmax/2 is the same as the original Km. Uncompetitive inhibition is when the inhibitor binds to only the enzyme-substrate complex, and inactivates it. This causes the number of active enzyme-substrate complexes to decrease, thereby decreasing Vmax. Km also decreases to exactly the same degree as Vmax. Since both kinetic factors decrease to the same extent, the slope of the Lineweaver-Burk plot of enzyme activity will be the same as for the uninhibited enzyme.
phosphatase v phosphorylase
phosphorylase- adds P group phosphatase- removed P group
carbonic acid
Compound that results from the combination of carbon dioxide and water H2CO3
Aldosterone
salt-retaining hormone which promotes the retention of Na+ by the kidneys. na+ retention promotes water retention, which promotes a higher blood volume and pressure, also exchanges K+ ions for Na+ ions, so it excretes K+ while reabsorbing Na+
