Biology Flashcards
Nucleolus
the site of production of rRNA transciption and processing. The size of the nucleolus is proportional to the amount of protein produced by the cell (more proteins, more ribosomes needed)
Rough endoplasmic reticulum
synthesizes all proteins (permits translation) that cross the membrane
Golgi body
source of transport tags for glycoproteins. Carbohydrates are necessary to produce the tags (glycosylation) needed for protein transport
Lysosomes
Contain enzymes that breakdown substrates, proteins (ex/ misfolded)
Peroxisomes
Responsible for the breakdown of long chain fatty acids by β-oxidation
Intermediate filaments
Proteins involved in cell-cell adhesion and integrity of the cytoskeleton
Obligate anaerobes
can not survive in an oxygen containing environment
Faculatative anaerobes
can use oxygen for aerobic metabolism if present or use anaerobic metabolism if it’s not
Aerotolerant anaerobes
unable to use oxygen but are not harmed by an oxygen environment
Gram negative bacteria
stains pink. Consist of thin peptidoglycan layer and outer membranes
Gram positive bacteria
stains dark purple. Consist of thick peptidoglycan layer
Episomes
A genetic element of bacteria that can replicate independently of the host
Virulence factors
traits that increase how pathogenic the bacteria is
Conjunction
Bacterial form of mating where a sex pili acts as a bridge for genetic material to cross. The transfer is unidirectional from the donor male (+) to the recipient female (-). Once the transfer is complete, the recipient (-) becomes a donor (+). Transfer between 2 donors (+) is not possible
Transduction
When a virus that carries genetic material from one bacteria to another through a vector
Transposons
Genetic elements that are capable of inserting and removing themselves from the genome
Lag phase
bacteria adapt to environment. Minimal growth occurs
Log (exponential) phase
bacteria adapt and grow exponentially
Stationary phase
Resources are limited and slows reproduction. The growth rate equals the death rate. The number of bacteria does not change
Death phase
resources are depleted
Virions
replicated progeny produced when a virus hijacks a host cell
Lytic cycle
Occurs when a virus begins to produce virions until the host cell lyses. Bacteria in the lytic phase are called virulent
Lysogenic cycle
Occurs when viral DNA is integrated in the host genome and is replicated
Prions
Infectious proteins that cause disease by triggering misfolding of other proteins
Interphase
consist of G1, S, and G2. Longest part of the cycle. DNA is in the form of chromatin
G₀ stage
when the cell is living and not doing anything to prepare for division. Occurs outside of G1
G₁ stage
Cells create organelles for energy and protein production. Cells must meet certain criteria like containing proper complement DNA
S stage
replication of genetic material. Chromosomes consist of identical chromatids (92 chromatids, still 46 chromosomes). Cells will now have double the DNA than G₁
G₂ stage
the cells checks to make sure DNA has been replicated correctly and if there is enough organelles and cytoplasm to divide
Telomeres
protective ends of chromosomes to protect DNA
Mitosis
when 2 identical daughter cells are created from a single cell. Occurs in somatic cells (non-sexual)
Prophase
The nuclear membrane dissolves and the nucleoli disappears. Chromatin condenses into chromosomes. Centrioles move to the edges of the cell and form spindle fibers
Kinetochores
serve as attachment points for kinetochore fibers in the center of centromeres
Metaphase
kinetochore fibers interact with spindle fibers and form the metaphase plate
Anaphase
sister chromatids are pulled apart when the kinetochore fibers are shortened
Telophase
Spindle fibers disappear. New nuclear membranes form around the chromatids
Meiosis
Gametocyte (germ cells) –> 4 non-identical gametes. It is 1 round of replication followed by 2 rounds of division
Meiosis I
reductional division and generates haploid daughter cells
Meiosis II
equational division and is similar to mitosis
Tetrad
a synaptic pair of 4 chromatids
Prophase I
Homologous pairs come together and intertwine in a process called synapsis. Crossing over occurs
Metaphase I
Tetrads align at the metaphase plate. Homologous pairs are lined up across from each other on the plate
Path of sperm
Seminiferous tubules —> epididymus —> vas deferens —> ejaculatory ducts —> nothing —> urethra —> penis
SEVE(N) UP
Seminipherous tubules
location of sperm production (spermatogenesis)
Spermatogonia
diploid stem cells
Leydig cells
secrete testosterone and androgens. Stimulated by LH
Sertoli cells
support cells. Stimulated by FSH. Secrete inhibin to feedback LH and FSH
Seminal vesicles
contribute fructose to nourish sperm
Ovaries
produce estrogen and progesterone
Primary oocytes
Formed during fetal development and have already undergone DNA replication. They are all diploid and arrested in prophase I
Secondary oocyte
arrested in metaphase II during ovulation unless triggered by fertilization
Fraternal (dixygotic) twins
form from fertilization of 2 eggs released during the ovulatory cycle
Identical (monozygotic) twins
form when a single zygote splits into two. If division is incomplete, conjoined twins can result
Stages of embryonic development
Zygote —> morula —> blastula —> gastrula —> neurula
Order of cell differentiation potency
Totipotent —> pluripotent —> multipotent —> non-potent
Ectoderm
Gives rise to integument, nervous system, and inner ear
Mesoderm
Develops into systems like the musculoskeletal, circulatory, and excretory. Also the gonads, adrenal cortex, connective tissue
Endoderm
Develops into epithelial linings of digestive and respiratory systems, pancreas, thyroid, bladder, and parts of liver
Selective transciption
only genes needed for a particular cell are transcribed and others are turned off
Induction
Ability of a group of cells to influence the fate of nearby cells by mediating chemical substances called inducers
Neural crest cells
Give rise to structures of the PNS
Brown fat
Releases more heat due to an insufficient ETC (due to an uncoupling protein). All infants generate heat due to inability to shiver. Contain multiple mitochondria
Teratogens
substances that interfere with early development. Ex/ alcohol, drugs, viruses, environmental chemicals
Autocrine
signals act on the same cell that secreted the signal
Paracrine
signals act on cells in a local area
Juxtacrine
signals stimulate receptors of an adjacent cell
Senescence
biological aging. At the cellular level this is due to shortened telomeres which results in the loss of genetic info
Foramen ovale
Connects R atrium and L atrium. This is important because it shunts blood away from the lungs and liver. The liver can not 1. Stand the high pressures and 2. Does not need the blood because it is not doing detoxification in the womb
Ductus arteriosus
shunts from pulmonary artery to aorta
Ductus venosus
Shunts from placenta via umbilical vein to IVC. This is important because this allows for max oxygenated blood to enter the heart
Gestational period
38 weeks (9 months, 280 days) from conception to birth. Gestation is measured from the last day of the menstrual period till birth (2 weeks before fertilization) = 40 weeks
Myelin
It increases the membrane resistance to ion leakage, allowing ions to travel farther. It decreases the capacitance of the axon when the thickness of myelin increases
Oligodendrocytes
produce myelin in the CNS
Schwann cells
produce myelin in the PNS
Synapse
nerve terminal, synaptic cleft, and post synaptic membrane
Astrocytes
nourish neurons and form the blood-brain barrier
Ependymal cells
Line the ventricles in the brain and produce CSF. Simple cuboidal
Microglia
phagocytic cells of the CNS
Ventral (anterior) root
efferent (motor) information
Dorsal (posterior) root
afferent (sensory) information
Spinal nerve
where the roots join before they divide into the rami. Sensory and motor
Anterior ramus
to the anterior component of the body, and the limbs
Posterior ramus
to the back (posture), skin
Layers of meninges
dura, arachnoid, pia
Subdural space
can become a potential space in a pathological situation (fluid can fill it). Ex/ subdural hematoma — blood collecting in this space
Subarachnoid space
contains the CSF
Extradural space
contains nerves, vessels, and fat. Location of epidural anesthesia injection
Resting membrane potential for neurons
-70 mV. The inside is (-) and the outside is (+)
Equilibrium potential of Na and K
-90 mV and 60 mV
Temporal summation
multiple signals are integrated during a relatively short period of time
Spatial summation
the additive effects are based on the number and location of the incoming signals
Absolute refractory period
no amount of stimulation can cause another AP to occur
Relative refractory period
a greater than normal stimulation can cause an AP because the membrane is starting from a potential that is more (-) than the RMP
Glutamate
excitatory NT that acts on the brain
GABA
inhibitory NT that acts on the brain
Asparate
excitatory NT that acts on the spinal cord
Glycine
inhibitory NT that acts on the spinal cord
Referred pain
Pain perceived at one location but it is not the site of the stimulus. Incoming signals from visceral and somatic afferents coming to the same spinal segment “confuse” the brain into thinking that the visceral pain is coming from elsewhere
Peptide hormones
Water soluble and travel through the blood. Short lived but effects are rapid. Charged and can’t pass through a membrane so they utilize the signaling cascade
Steroid hormones
Not water soluble and need carrier proteins. Lipid soluble and can easily cross the cell membrane (receptors are intracellular). Slower but are longer lived.
Tropic hormones
Hormones that stimulate an intermediate that secretes a hormone. Ex/ GnRH stimulates LH to release testosterone/estrogen from the gonads, CRF, TRH
Direct hormones
secreted and act on a target directly. Ex/ insulin
Anterior pituitary hormones
FSH, LH, ACTH, TSH, Prolactin, Endorphins, GH
FLAT PEG - flat are tropic, peg are direct
Prolactin
Stimulates milk release from mammary glands. Prolactin release is under the inhibitory control of dopamine release from the hypothalamus
Endorphins
decrease pain perception
Growth hormone
promotes growth of bone and muscle, and fatty acid breakdown (B oxidation)
ADH
Released from the posterior pituitary. Increases reabsorption of water from collecting duct of kidney. Low blood pressure, low blood volume (baroreceptors), or high plasma osmolarity (osmoreceptors) cause its release
Oxytocin
Released from the posterior pituitary. Stimulates uterine contractions during labor and contraction of smooth muscle in the breast during lactation. Has a positive feedback loop
Hypothyroidism
Thyroid hormones are not secreted in sufficient amounts. Leads to lethargy, decreased body temp, slow HR, and weight gain
Calcitonin
Decrease plasma Ca levels by increasing secretion from kidney, decreasing absorption in gut, and increasing storage in bone
Thyroid
sets the basal metabolic rate through T₃ and T₄, and controls calcium homeostasis through calcitonin
Parathyroid hormone
Activates vitamin D which is required to absorb Ca and phosphate in the gut
Glucocorticoids
Regulate glucose levels. High glucocorticoid levels –> increased insulin levels –> increased fat storage
Mineralocorticoids
regulate salt and water homeostasis
Aldosterone
mineralocorticoid that increases Na+ reabsorption from the distal tubule and collecting duct. Water follows the Na+ to increase BP and BV. Primarily under the control of RAS
RAAS system
The kidney’s response to decreased BP. Renin (juxtaglomerular cells) cleaves angiotensinogen –> active angiotensin I –> angiotensin II (ACE in lungs) –> release of aldosterone (adrenal cortex) –> increased Na+/H2O –> increased plasma volume –> increased CO –> increased BP
Adrenal medulla
Responsible for the production of epinephrine and norepinephrine. These can be released in response to the SNS and some neurons
Adrenal cortex
Secretes corticosteroids (steroid hormones). 3 S’s: Salt, Sugar, Sex
Glucagon
released by α cells to increase glucose levels
Insulin
released by β cells to decrease glucose levels. Stimulates fat and protein synthesis. Increases amount of GLUT 4 on the cell membrane
Hyperglycemia
causes excess glucose in the urine which cause excess water excretion (increase urine volume)
Type 1 diabetes
autoimmune destruction of β cells
Type 2 diabetes
receptor level resistance to insulin
Somatostatin
Inhibits glucagon, insulin, and GH release. Produced by delta cells and the hypothalamus
Testes
secrete testosterone in response to LH and FSH
Ovaries
secrete estrogen and progesterone in response to LH and FSH
Estrogen
has positive and negative feedback effects. Estrogen levels initially negatively feedback on the hypothalamus and pituitary in order to allow the egg to grow (follicular phase), but it also positively feedback on those structures when the threshold is met and its time for ovulation
Pineal gland
Secretes melatonin at night and serotonin during the day. Involved in the maintenance of circadian rhymes
Erythropoietin
stimulate bone marrow to produce RBC’s in response to low blood O₂ levels
Atrial natriuretic peptide (ANP)
Regulates salt and water balance. When the atria are stretched, ANP promotes Na excretion (increase urine vol) to decrease BP and BV
Pathway of air
nares—> pharynx —> larynx (glottis)—> trachea —> bronchi —> bronchioles —> alveoli
(You Pop before you Lock )
Residual volume
the small amount of air you have once all air has been breathed out of your lungs
Vital capacity
max amount of air you can move. IRV + TV + ERV
Tidal volume
Normal 500 mL of air you breath in and out. TV will increase in times of low pO2 (high altitude) —> increased air inhaled
Dead space
No gas exchange occurs, but air still flows through these areas
Chemoreceptors
primarily sensitive to to changes in CO₂ concentration and osmolarity
Polycythemia
RBC multiplies due to conditioning at high altitudes. So the O2 carrying capacity is enhanced to take advantage of whatever O2 available
Vasoconstriction
Causes conservation of thermal energy because blood is not able to pass as easily
Vasodilation
causes dissipation of thermal energy when more blood passes through vessels
Lysozyme
Innate immune enzyme that attacks the peptidoglycan walls of gram negative bacteria. Found in mucus of respiratory passages, tears, and saliva
Oxygen dissociation curve
Measure of oxygen levels that are bound to a certain percentage of a Hb molecule.
Things that move the curve to the left = Hb increased affinity for O2
Things that move the curve to the right = Hb decreased affinity for O2 (oxygen unloading)
Semilunar valves
separate the ventricles from the vasculature
Tricuspid valve
separates the R atria and R ventricle
Bicuspid (mitral) valve
separates the L atria and L ventricle
Pulmonic valve
separates the R ventricle from the pulmonary artery
Aortic valve
separates the L ventricle from the aorta
Path of electrical conduction in heart
SA node —> atria —> AV node —> bundle of His —> purkinje fibers —> ventricles
Hepatic portal system
blood leaving a capillary beds in the gut will pass through the hepatic portal vein before reaching capillaries in the liver
Hypophyseal portal system
blood leaving capillary beds in the hypothalamus travels to capillaries in the anterior pituitary (for paracrine secretion)
Renal portal system
blood leaving capillaries in the glomerulus travels through the efferent arteriole to the vasa recta
Hematocrit
volume of RBC / volume of whole blood
Granulocytes
Neutrophils, eosinophils, basophils. They contain cytoplasmic granules that are toxic to invaders. Released by exocytosis.
Agranulocytes
Lymphocytes (primary responders) and monocytes
Thrombopoietin
secreted by the liver and kidney and stimulates platelet development
Blood pressure
ΔP = CO x TPR
Baroreceptors
stimulate the SNS to increase vasoconstriction when BP is low and decrease it when BP is high
Systolic blood pressure
occurs when the ventricles are contracting and blood is pumped into the lungs and aorta
Diastolic blood pressure
occurs when the ventricles are refilling
Cooperativity
Binding of 1 oxygen changes the conformation of hemoglobin (taught to relaxed) which increases the affinity for other oxygen molecules and increases the positive feedback of binding
Bicarbonate buffer system equation
CO₂ + H₂O –> H₂CO₃ –> H⁺ + HCO₃⁻
*reversible
Hydrostatic pressure
force that blood exerts against vessel walls
Osmotic pressure
force generated by solutes to keep water in the blood stream. It is usually called oncotic pressure because it relates to plasma proteins
Spleen
stores blood and activates B cells (mature and turn into plasma cells to produce antibodies) (adaptive immunity)
Thymus
located in front of the pericardium. It produces T cells that kill infected cells directly (cytotoxic immunity)
Adaptive immunity
defined by the presence of lymphocytes, either T or B cells, and includes both CD8+ cytotoxic T cells, CD4+ helper T cells, and B cells that present antigen and produce antibodies
Innate immunity
Always active against infection but can not target specific invaders. Also called non-specific immunity
Lymph nodes
Areas when immune cells group up to attack. B cells are activated here
Gut associated lymphoid tissue (GALT)
immune tissue near the digestive tract. It includes tonsils and adenoids in the head, Peyer’s patches in the SI, and the appendix
Lymphocytes
Agranulocytes responsible for antibody production, immune system modulation, and targeting of infected cells. Include NK cells, B lymphocytes, and T lymphocytes
Monocytes
Phagocytic cells in the bloodstream. They become macrophages in the tissue. Ex/ microglia, langerhans cells, osteoclast
Complement system
System that consists of proteins that act as nonspecific defense to bacteria in the blood. The classical pathway requires antibody binding and the alternative pathway does not
Interferons
Proteins that are transcribed to prevent viral replication in other cells. They decrease the permeability of cells to make it harder for viruses
Major histocompatibility complex (MHC)
protein that binds to the pathogen and carries it to the surface for adaptive immunity cells
MHC class I
binds proteins already within the cells through an endogenous pathway
MHC class 2
Binds invading antigens in an exogenous pathway. They display antigen presenting cells like macrophages and dendritic cells in the skin
Macrophages
They endocytose invaders, digest them with enzymes, then present pieces of the invader to other cells by using MHC
Natural killer cells
If a pathogen finds a way to down regulate MHC molecules, NK cells detect this and induce apoptosis in those infected cells
Opsonized bacteria
bacteria marked with an antibody from a B cell that can be targeted by immune cells (phagocytize)
Neutrophils
Phagocytic and target bacteria. They use chemotaxis to sense certain products given off by bacteria and follow them back to the source
Eosinophils
Allergic reactions and invasive parasitic infection. They release histamine that causes inflammation by vasodilation and movement of fluid and immune cells from the blood to tissues
Basophils
allergic responses
Mast cells
release histamine and increase leakiness of capillaries in order for immune cells to leave the blood stream and into tissues
Humoral immunity
involves the production of antibodies (immunoglobulins) produced by B cells (plasma cells)
Clonal selection
When the adaptive immune system encounters an antigen, cells with receptors specific to the antigen are presented. The cells with the highest affinity for a given antigen proliferate
Variable region (domain)
Tip of the Y. Also called the antibody binding region. Antibodies develop specificity so slowly because this region hypermutates to match the antigen
Constant region (domain)
The long part of the Y. It contains receptors for NK cells, monocytes (macrophages) and eosinophils to initiate the complement cascade
5 isotypes of antibodies
IgA, IgD, IgE, IgG, IgM
Helper T cells (CD4⁺)
Coordinates the immune response and secretes lymphokines. They respond to MHC-II. Most effective against bacterial, fungal, and parasitic infection. Ex/ loss of these cells occurs in HIV infection
Lymphokines
Secreted by lymphocytes to recruit other immune cells (plasma cells, cytotoxic T cells, macrophages) to an area and increase their activity
Cytotoxic T cells (CD8⁺)
Directly kill virally infected cells by injecting toxins and causing apoptosis. They are better at fighting intracellular infection. Respond to MHC-I
Suppressor (regulatory) T cells
They help tone down the immune response once infection has been contained (self-tolerance)
Autoimmunity
when the immune system fails to distinguish between self and foreign
Active immunity
the immune system is stimulated to produce antibodies against a specific pathogen after a weakened form of the antigen is presented (vaccines)
Passive immunity
transfer of antibodies to an individual. Only the antibodies, not the plasma cells, are transferred. Ex/ mother to child through breast feeding
Ghrelin
Released in the stomach when chyme is in the intestines. It stimulates hunger by stimulating the peptide NPY in the arcuate nucleus
Leptin
Satiety hormone released from adipose tissue in response to glucose and insulin circulating. It suppresses NPY and appetite
α-amylase
starts digestion of starches into carbohydrates by breaking their linkages
HCl (digestion)
Secreted by parietal cells. Causes chemical breakdown of molecules and increase surface area of food so certain enzymes work
Intrinsic factor
Secreted by parietal cells. Important for protection of vitamin B12 from pancreatic proteases
Pepsinogen
Secreted by chief cells. Proteases that are cleaved to pepsin by the acidic environment
Gastrin
Secreted from antrum G cells in the crypts into the blood. Stimulates motility in the intestines and stimulates parietal cells to secrete HCl
Lipase
Secreted by chief cells. Continues hydrolysis of lipids
Histamine (digestion)
It is the primary stimulus for HCl secretion
Somatostatin (digestion)
Decreases HCl secretion, gastric emptying, GI motility, and GI hormone release. Works directly on parietal cells
Brush border enzymes
Digest oligosaccharides and disaccharides into monosaccharides in the small intestine. Monosaccharides are the only form of carbohydrates that can be digested
Enteropeptidase (enterokinase)
Activates trypsinogen in the SI and forms trypsin. Trypsin activates all the other pancreatic proteases to digest proteins into oligopeptides
Dipeptidase
cleaves dipeptides to release free AA
Aminopeptidase
removes the N-terminal AA from a peptide
Secretin
Secreted by centroacinar cells in response to acid (chemoreceptors) —> increase pancreatic and intestinal buffers —> neutralizes acid. Causes the pH to lower to
Chloecystokinin (CCK)
secreted by acinar cells in response to the entry of chyme in the duodenum. It stimulates bile production in the liver, gallbladder contractions, and relaxation of the sphincter of Oddi. It also stimulates digestive enzyme release from the pancreas
Albumin
maintains oncotic pressure and is a carrier for clotting factors
Net filtration pressure
HPg - (𝛑g + HPbs)
Starling forces
Hydrostatic and oncotic pressure in the glomerulus and Bowman’s space
Diuretics
inhibit reabsorption of Na in order to increase secretion
Layers of epidermis
Stratum corneum, *stratum lucidum, stratum granulosum, stratum spinosum, stratum basale
(Come, Lets Get Sun Burned)
*Stratum lucidum is only present in thick hairless skin like the palms
Langerhans cells
macrophages in the stratum spinosum. Present antigens to T cells
Anion gap
We have our main cations in the plasma (Na and unmeasured) and our main anions as well (Cl, HCO3, and unmeasured). The anion gap is just the space (difference) between the Na and Cl in our plasma. When the anion gap is higher than normal, that means we have an acid gain. When the anion gap is normal, we have a base lose (losing HCO3
Metabolic acidosis
A decrease in pH and a decrease in H2CO3 and compensates by decreasing pCO2
Metabolic alkalosis
An increase in pH and an increase in H2CO3 and compensates by increasing pCO2
Type 1 fibers
Slow twitch red fibers. They have high myoglobin content and derive energy aerobically. Ex/ muscles that support posture
Type 2 fibers
Fast twitch white fibers. They contain less myoglobin and less iron. They contract rapidly but fatigue easily
Myogenic activity
when smooth muscle can contract without NS input. Both smooth and skeletal muscle can exhibit this
Myosin
Thick filament
Actin
Thin filament and contains troponin and tropomyosin
Sarcolema
Cell membrane of the myocyte. Able to propagate an AP
T tubules
Distributes the AP of a myocyte to all sarcomeres
Frequency summation
when prolonged exposure to a stimulus causes contractions to become stronger and longer
Tetanus
muscle inability to relax after frequency summation. Prolonged tetanus results in muscle fatigue
Vitamin D
activated by PTH and also promotes bone resorption
Genes
DNA sequences that code for heritable traits
Allele
Alternative form of a gene. Genetic combination is the genotype and the observable trait is the phenotype. It is classified by the degree of penetrance
Locus
Particular location on a chromosome where alleles for a gene reside.
Hemizygous genotype
only 1 allele is present for a given gene. Ex/ X chromosome in males
Complete dominance
1 dominant and 1 recessive allele exists for a given gene
Codominance
when more than 1 dominant allele exist for a given gene
Incomplete dominance
when a heterozygote expresses a phenotype that is between (intermediate) the 2 homozygous genotypes. Ex/ RR (black hair) x rr (white hair)—> 4 Rr (grey hair)
Autosomal dominant trait
autosomal means it is associated with one of the non-sex chromosomes. Dominant means you get one allele from the mother and one from the father
Autosomal recessive trait
Presence of 2 defective genes. All children are effected because they receive a mutated allele from both parents
Y-linked inheritance
when the only effected individuals are males
X-linked dominant vs. X- linked recessive
1 copy of a defective gene is necessary for the diseased phenotype vs. 2 copies of a defective gene, one on each X chromosome, are necessary
Penetrance
A population measure where there is a certain proportion of the population with a given genotype that actually expresses the phenotype
Full penetrance
An individual has over 40 sequence repeats and would show symptoms of a disease
High penetrance
Fewer sequence repeats and may or may not show symptoms
Reduced pepentrance
Almost no sequence repeats and no symptoms
Expressivity
The variability in phenotypes for the same genotype in an individual
Transposons
insert themselves into the genome and can disrupt the gene if they are within the coding sequence
Genetic leakage
Flow of genes between species. Individuals from different but closely related species can mate and produce hybrid offspring
Genetic linkage
The tendency of genes located close together on a chromosome to be inherited together during meiosis
Genetic drift
the change in composition of a gene pool by chance (Ex/ random mutations)
Founder effect
Extreme type of genetic drift where a small population leads to isolation from other populations due to natural barriers, or bottlenecks. This leads to inbreeding
Test cross
Used to determine an unknown genotype. The unknown genotype (Px where x = P or p) is crossed with an organism known to be homozygous recessive (pp)
Recombination frequency
The likelihood of 2 alleles seperating from each other during crossing over is proportional to the distance the genes are from each other on the chromosome. Genes farther apart are more likely to cross over
Hardy Weinburg equillibrium
Tells us when gene frequencies of a population are not changing and are stable
p² +2pq +q² = 1
p + q = 1
- Where p is the frequency of the dominant allele and q is for the recessive
p² = frequency of homozygous dominant allele
2pq = frequency of heterozygotes
q² = frequency of homozygous recessive allele
Inclusive fitness
a measure of an organisms success in a population
Polymorphisms
naturally occurring differences between members of the same population
Speciation
formation of a new species though evolution
Divergent evolution
From a common ancestor, 2 species develop different characteristics. Ex/ humans and monkeys
Parallel evolution
2 species independently evolve in similar ways
Convergent evolution
development of similar characteristics with no common ancestor. Ex/ fish and dolphins
Corticosteroids
Glucocorticoids, mineralocorticoids, and cortical sex hormones
Refractory period
period of time following an AP where a neuron is not able to depolarize
Relative vs. absolute refractory period
Greater than normal stimulation can cause an AP vs. no amount of stimulation is able to cause an AP
Corticotropin releasing factor (CRF)
tropic hormone released from the hypothalamus that causes ACTH releases from the anterior pituitary
Gonadotropin releasing hormone (GnRH)
tropic hormone released from the hypothalamus that causes LH and FSH release from the ant. pit.
Thyroid releasing hormone (TRH)
tropic hormone released from the hypothalamus that causes TSH release from the ant. pit
Orthologous genes
homologous genes where a gene diverges after a speciation event, but the gene and its main function are conserved
Hershey-Chase experiment
Used to determine that DNA is heritable genetic material. They injected bacteriophages with radiolabeled DNA (phosphorus) and protein (sulfur) and allowed them to infect non-labeled bacteria. Only the DNA was found in the cells
Functions of lymphatics
Removal and destruction of pathogens, drain excess fluid from interstitial spaces (not the CNS), absorb fats from the GI tract.
Cytokines
Chemical substances released by macrophages that stimulate inflammation and recruit additional immune cells to the area
Isotype switching
Cells can change which isotype of antibody they produce when stimulated by specific cytokines
Constant expressivity
If expressivity is constant, all have the same phenotype
Variable expressivity
If expressivity is variable, there are people with the same genotype but varying phenotypes
Disruptive selection
Occurs when two extreme phenotypes are selected over the norm (no incomplete dominance) leading to the creation of subpopulations that grow more disparate over time (speciation)
Collagen
Principal extracellular component of connective tissue
In vivo
refers to when research or work is done with or within an entire, living organism
In vitro
used to describe work that’s performed outside of a living organism
Testosterone
Secreted by leydig cells in the testes. Associated with risky and aggressive behavior (secretion increases during puberty)
Diabetic ketoacidosis
Insufficient insulin in the body causes the body to break down fatty acids into acidic ketone bodies. Causes increased excretion of glucose (decreased absorption), H+, and water
Smooth endoplasmic reticulum
Lipid synthesis (steroids, oils, wax) and detoxification of certain drugs
Directional selection
The shift in allele frequencies of a population to variants of one extreme
Orexigenic vs. anorexigenic peptides
Peptides that increases appetite vs. peptides that suppress appetite
Effects of acute vs. long-term stress
PNS is suppressed to divert resources to immediate problems vs. energy is used to cope with stress must be replaced like increasing appetite and sleep
Chemiosmosis
The movement of ions across a semipermeable membrane, down their electrochemical gradient
ABC transporters
ATP binding cassete transporters are transmembrane proteins that are membrane associated ATPases
Vibrissae
Nasal hairs
Node of Ranvier
Unmyelinated regions of a neuron that allow for saltatory conduction of action potentials. These are the only places where ion exchange occurs
Diploid vs. haploid
Containing 2 copies of each chromosome (2n) VS. containing 1 copy of each chromosome (n)
Negative feedback loop
Used to maintain homeostasis. A change in a physiological variable triggers a physiological response that counteracts the initial variable
