Biology Flashcards
How often does menstruation occur?
One egg per month ovulated into peritoneal sac
- Drawn into fallopian tube
- Fallopian tubes have cilia which propel egg forward to uterus
Portal system definition
Two capillary beds in series through which blood travels before returning to the heart
Paracrine signals
Signals act on cells in a certain area
Calcitonin effect
Dec. Ca absorption from gut, inc storage of Ca in bone, inc Ca excretion from kidneys
Hook (flagella)
Connects filament and basal body so that as basal body rotates, it exerts torque on filament and spins/propels bacterium forward
Apoptosis
Programmed cell death
How are primary germ layers formed?
When cells migrate from blastocoel remains
Binary fission
Asexual reproduction of prokaryotes
- Circular chromosome attaches to cell wall while replicating
- Produces two identical daughter cells
Founder effect
extreme case of genetic drift when smalll population finds itself in reproductive isolation from other populations
-Inbreeding leads to homozygosity and inc prevalence of homozygous dominant and recessive genotypes
Function of cell wall
Forms outer barrier of cell
- Provides structure
- Controls movement of solutes in/out
WHat are fingerhails and nails composed off
Keratin
Mineralcorticoids function
Salt and water homeostasis in kidneys
Dizygotic Twins process of fertilization
Two different eggs released during one ovulatory cycle
-Fertilized by two different sperm
Where do solutes reabsorbed in PCT go?
They enter the insterstitium then pass through the vasa recta and return to the bloodstream
What hormone affects TSH release?
TRH
How is fertilzation by multiple sperm stopped?
After penetration by a sperm, cortical reaction occurs -> release of Ca2+ ions
- Depolarizes membrane
- Inc metabolic rate of newly formed diploid zygote
What are the three processes kidney uses to regulate blood volume and osmolarity
filtration, secretion, reabsorption
Pleural Cavity of Lungs
Filled with lubricating fluid secreted by the membranes
How to germ cells divide?
Meiosis
What type of cells are germ cells?
Haploid
Luteal phase
LH causes ruptured follicle to form corpus luteum
- Prog levels start to rise
- Prog maintains uterine lining for sperm implantation
- Estrogen levels remain low
- High levels of prog cause negative feedback of GnRH, LH, FSH -> prevents ovulation of multiple eggs
Differences between oogenesis and spermatogenesis
- limited supply of stem cells
- By birth, all oogonia are primary oocytes and arrested in prophase1 - oogeneis creates one oocyte instead of four mature spermatocytes
- Secondary oocyte arrested in metaphase II until fertilization
When is the second checkpoint of the cell cycle and what is checked?
End of G2
- Ensures DNA replication had no errors
- Ready to enter mitosis
How do viruses reproduce?
After infection, translation of viral genetic material must occur for reproduction
- DNA viruses have to enter nucleus before transcription and translation
- Positive sense viruses stay in cytoplasm for direct translation
- Once viral genome is replicated, can be packaged in capsid to infect other cells
Adrenal glands location
On top of kidney
Prostate gland and seminal vesicles work together to?
Give seminal fluid mildly alkaline properties so sperm can survive in relative acidity of female reproductive tract
Death phase of bacterial growth
Once bacteria have exceeded ability/resources of environment to support them
-Mass death of cells
What causes parturition/pregnancy
Accomplished by rhythmic contractions of uterine smooth muscle and coordinated by prostaglandins and oxytocin
Loop of henle located in what region of kidney?
Descends and ascends in outer/inner medulla
What vascular structures are contained in the umbilical cord?
Two arteries and one vein
- Arteries carry deoxygenated blood and waste back to mother
- Vein carries oxygenated blood and nutrients to baby
What do FLAT and PEG mean in FLAT PEG
FLAT: tropic hormones
PEG: direct hormones
Neo-darwinism changes to include recombinatino
Differential reproduction: populations evolve not individuals
-When recombination or mutation results in favorable change, change is more likely to be passed on to next generation
What is Oogenesis
Production of female gametes
What hormone does the heart release
Atrial natriuretic peptide
Equations of harvey weinberg equilibrium
p+q=1 p^2 + 2pq + q^2 = 1 -p=dominant allele freq -q=recessive allele freq -p^2 = freq of homozygous dominant -2pg = freq of heterozygote -q^2 = freq of homozygous recessive -p^2 + 2pq = freq of dominant phenotype
Internal urethral sphincter
Composed of smooth muscle
- Contracted in normal state
- Under involuntary control
How does mitosis occur in germ cells
Mitosis only occurs in somatic cells
Senescense
Biological aging
-Occurs at cellular and organismal levels
Plasmids
Carry DNA not necessary for survival of prokaryotic cell but can help with antibiotic resistance
-Could carry virulence factors that increase pathogenecity
Dermis def
Contains Papillary layer and reticular layer of skin
Papillary: Composed of loose connective tissue
Reticular layer: Below papillay and much denser
Cortisol function
Raise blood gluc by inc gluconeogenesis and dec protein synthesis
-Dec inflammation and immunologic response
What are the female gonads
Ovaries: produce estrogen and progesterone
Calcitonin produced by?
Follicular cells produce parafollicular cells in thyroid
What energy source do the use sperm use?
fructose
Where are the ovaries located?
Thousands of follicles located in pelvic cavity
How does growth hormone perform its function?
Prevents glucose uptake in some tissues and stimulates fatty acid breakdown
Speciation def
Formation of a new species via evolution
-Could occur based on isolation of two populations
Amnion
Surrounds allantois
-Thin tough membrane filled with amniotic fluid
Chorionic villi
penetrate endometrium and support maternal-fetal gas exchange
Neurulation
Development of nervous system
- Rod of mesodermal cells called notochord forms along axis of organism
- Neural folds grow towards each other and form neural tube = CNA
- Neural crest cells at tip of folds migrate outwards to form PNS and specific cell types
- Ectodermal cells migrate to neural tube to cover nervous system
Stratum granulosum def
Keratinoctytes die here and lose their nuclei
How long is the effects of steroid hormones?
Slower but longer-lived effects than peptide hormones
Asters
Anchor centrioles to cell membrane
Ascending loop of henle permeability
Only permeable to salts
-Impermeable to water
Function of amniotic fluid
Shock absorber for maternal motion
What is gastrulation?
Generation of three distinct cell layers
-Forms primary germ cell layers
Gram negative cell wall
Thin layer with peptidoglycan
- Cell walls separated from membrane by periplasmic space
- Outer membrane has phospholipids and lipopolysaccharides
- Stain pink
Where are parathyroid hormones located?
On top of posterior surface of thyroid
Islates of langerhan function
Small clusters of hormone producing cells grouped together
Seminal vesicles
Contribute fructose to nourish sperm
What are the three types of hormones released by pancreas
Alpha, beta and delta cellls
When is erythropoietin protein secreted
In response to low O2 levels in blood
Angiotensin aldosterone system steps
- Dec BP-> juxtaglomerular cells in kidney secrete renin
- Renin cleaves inactive angiotensinogen into active angiotensin I
- Angiotensin I converted into angiotensin II by angiotensin-converting enzyme
- Angiotension II stimulates adrenal cortex to secrete aldosterone
- Once BP restored, Renin no longer released
- Negative feedback
What are starling forces
Govern movement of fluid into Bowman’s space
-Account for H-static and oncotic pressure differentials between blood and Bowman’s space
Indeterminate vs determinate cleavage
Determinate: cells are already determined
-COmmitted to differentiations into a certain cell type
Indeterminate: Cells can still develop into complete organisms
Parallel evolution
When related species evolve in a similar way for a long period of time
How do X-linked diseases work?
If recessive, female needs allele on both X chromosomes
- If only have allele on one X chromosome -> carrier
- For males, only have one X chromosome so if they carrier the allele, have disease
Genetic drift def
Changes in gene pool due to chance
-More pronounced in small populations
How does the hypothalamus regulate pituitary gland?
Via tropic hormones
-Paracrine release into portal system
What phenomenon is melatonin related to
Circadian rhythms
What stimulates calcitonin secretion?
High levels of Ca2+ in blood
Reticular Fibers
Made of collagen proteins
- Arranged in thin networks
- Net arrangement as a support network
Menstruation steps
- Corpus luteum loses stimulation from LH
- Prog levels decline
- Uterine lining sloughed off
- Lower levels of estro/prog allow GnRH to be released and next cycle to begin
Vaginal birth alternate name
Parturition
Osmotic pressure vs oncotic pressure
Osmotic: sucking pressure that draws water into vasculature
Oncotic: Osmotic pressure attributable to dissolved proteins specifically
Micturition reflex
- When bladder full, stretch receptors tell nervous system to empty it
- Parasympathetic neurons fire causing dtrusor muscle to contract
- Internal sphincter relaxes
- Individual then has choice to mtaintain tone of external to prevent urination
Complete dominance def
When only one dominant and one recessive allele exist for a gene
Regenerative capacity
Ability of an organism to regrow certain parts of the body
-Stem cells can migrate to appropriate part of body to initiate regrowth
What does GnRH trigger during puberty
Triggers anterior pituitary to synthesize and release FSH and LH
Type I Alveolar Cell
Simple Squamous Epithelial
-Main site of gas exchange
What hormone affects ACTH release?
CRH
What process does zygote undergo during its travel to uterus?
Rapid cell division -> cleavage
-Oficially creates embryo
Protein fibers vs Ground substance
Protein fibers: Strengthen and Support tissue -Secreted by connective tissue cells —Collagen —Elastic —Reticular
Ground substance:
- Material between cells and fibers
- Supports and bind cells
- Stores water
- fluid, semi-fluid, gelatinous, calcified
- Contains Glycosaminoglycans
Chromosomal mutations insertion
When a segment of DNA is moved from one chromosome to another
Obligate aerobes
Require O2 for metabolism
Totipotent stem cells
Can divide into any cell type
-Prior to formation of germ layers
What does fewer sequence repeats of an allele indicate?
reduced, low or non penetrance
Constant vs variable expressivity
COnstant: All inviduals with same genotype express same phenotype
Variable: Individuals with same genotype can have different phenotypes
Microfilaments
Made of actin -> organized into bundles
- Resist compression/fractre -> protection
- Role in cytokinesis -> contained in cleavage furrow
Stationary phase of bacterial growth
As number of bacteria inc, resources are reduced
-Reproduction slows
What is the functional unit of the kidney
The nephron
Penetrance def
Population metric that measures proportion of individuals carrying a certain allele who actually express the phenotype
-Probability that given a particular genotype, person expresses the phenotype
Type II Alveolar Cell
Simple Cuboidal Epithelial
-Secretes Alveolar fluid and surfactant
Alveolar fluid: keeps surface between cell and air moist
Surfactant: Prevents alveolar collapse -> keeps alveoli open
How do peptide hormones signal for cellular change?
After bidning to extracellular receptor, induce signaling cascade
- 1st messenger is peptide hormone that binds to receptor
- Trasmission of 2nd signal/messenger triggered
- 2nd messenger affects the intended change
Long term stress hormone vs Short term stress
Cortisol = long term Catecholamines = short term (epi/norepi)
Functions of excretory system
Regulation of blood pressure
Reulgation of blood osmolarity and acid-base balance
Removal of nitrogenous waste
Function of ascending vs descending loops of henle
Descending: Maximizes water reabsorption
Ascending: max salt reabsorption
What cortical sex hormones released by adrenal glands
Androgens and estrogens
How do T3 and T4 affect change?
Make energy production more/less efficient and alter utilization of glucose and fatty acids
-Higher T3 = more cellular respiration
ER
SEries of interconneted membranes continuous with nuclear envelope
Genes
DNA sequences that code for heritable traits passed from generation to the next
-Organized on chromosomes
G2 Postsynaptic Gap phase
Further protein syntehsis and rapid cell growh
- Microtubules being to reorganize to form a spindle
- Second checkpoint
Parts of a mature sperm
Head: cap with acrosome
Mid piece: filled with mitochondria to generate ATP for swimming through reproductive tract
Flagellum: motility
What mutations occur in species well suited to their habitat
No changes ar elikely to occur
What Is Mendel’s 2nd Law and what aspect of meiosis explains it?
INheritance of one allele has no effect on likelihood of inheriting alleles for other genes
-Explained by crossing over
Chromosomal mutations Deletion
Large segment of DNA lost from chromosome
Full penetrance sequence repeats
40 sequence repeats
100% of individuals with allele show phenotype
Where does fertilization occur?
Widest part of fallopian tube -> ampulla
Puncuated equilibrium
Change in some species occurs in rapid bursts instead of gradually over time
Prolactin function
Stimulates mmilk production in mammary glands
-Smooth muscles in breast contract
Stratified Squamous Epithelium
First line of defense against microbes -> protection against abrasion of water loss
- Nonkeratinized: Mouth, tongue, pharynx, esophagus, vagina
- Keratinized: Superficial layer of skin
Tight Junctions vs Adherens Junctions
Tight: Form fluid-tight seals between cells
- Preventing substances from passing through -> no leaky organs
- Lining of stomach, intestines, bladder
Adherens: Help epithelial surfaces resist separation during movement
-Connect actin cytoskeleton of cells together
Blastula structure
Hollow ball of cells in fluid-filled cavity
Bacterial shapes
Spherical = cocci
Rod-shaped bacteria = bacilli
Spiral-shaped = spirili
Zona Pellucida
Surrounds oocyte and a cellular mix of glycoproteins to protect oocyte and compounds needed for sperm binding
Where do spermatozoa gain mobility
Sperm are passed to epididymis where they gain mobility
What substances are always reabsorbed
Glucose, vitamins, amino acids
What drugs inhibit ADH release and what are their effects
Caffeine and alcohol inhibit ADH release
-Lead to freq urination of dilute urine
Law of Segregation
Either chromosome can end up in either daughter cell
Directional selection ef
Emergence and dominance of initially extreme phenotype
what hormones does adrenal medulla release
Promote sympathetic hormones epi and norepi
Cowper’s/Bulbourethral Gland
Produces clear viscous fluid that clears out remnants of urine and lubricates urethra during sexual arousal
Areolar Connective tissue
Strength, elasticity, support
- In and around nearly every structure
- Packing material
Facultative Anaerobes
Can toggle between anaerobic and aerobic metabolism based on O2 concentration
Direction of genetic info transfer in conjugation
Male donor to recipient female
-Male donor needs plasmids for sex factors
Where are the testis located
In the scrotum (external pouch below penis)
Peroxisomes
Contain hydrogen peroxide
-Break down of long chain fatty acids via beta oxidation
Types of amino acid derivatives?
Epi and norepi
-Catcholamines
Punnet square variables
P generation = parent -> gets crossed
F1 generation = their offspring
F2= offpsring of the offspring
When does menstruation occur
Only if implantation doesn’t occur
Transitional Epithelium
Allows urinary organs to stretch
- Maintains protective lining without rupturing
- Urinary bladder and portions of ureters and urethra
High penetrance sequence repeats
Fewer sequence repeats
Most with allele show phenotype
Filtration steps
- Fluid moves into Bowman’s spaces based on Starling forces
2, Hydrostatic pressure in glomerulus much higher than that in Bowman’s space so fluid moves into nephron
-This diff in H-static pressure overrides higher osmolarity of blood in Bowman’s space that opposes fluid movement into nephron
Structure of Bacteriophages?
Tail sheath: syringe that injects genetic material into bacteria
Tail fibers: help bacteriophage recognize and connect to correct host cell
Contrast R from L Lung
R lung:
-Shorter, wider, 3 lobes
L lung:
-longer, narrower, two lobes, cardiac notch
Erythropoietin function
Stimulates bone marrow to inc erythrocyte production
What is descending loop of henle mostly permeable to?
Primarily permeable to water
Juxtacrine
Involve a cell directly stimulating receptors of an adjacent cell
What does respiratory system do if blood pH too high
Decreases respiratory rate
-Increased conversion of CO2 and water in forward direction of equation to create more H+ and HCO3-
How does ADH affect kidney function
Only in colelcting duct
- Inc reabsorption of water
- Greater water retention/more concentrated urine
Yolk sac function
Site of early blood cell development
Conjugation
Bacterial mating/sexual reproductions
- Two bacterial cells form conjugation bridge: facilitates transfer of genetic material
- Transfer is unidirectional
- Bridge made from sex pili from donor male
- Copy of genome attempted to transfer but usually not completed
Where do peptide hormones bind?
They are charged so they cannot pass through the phospholipid bilayer
-Bind to extracellular ligand
How is viral progeny released?
Released when cell death initiated by virus
- Spills progeny
- Could also result from host cell lysing by large numbers of virion
- Can also be by fusing with cell membrane -> productive cycle
What system controls aldosterone secretion
angiotensin aldosterone system
Episomes
Plasmids capable of integrating into genome of bacteria
Glucocorticoids function
Steroid hormones that regulate glucose levels
Negative sense single stranded virus RNA
Strand is template for synthesis of complementary strand
- Complementary strand used as template for protein synthesis
- Must have RNA replicase to ensure complementary strand synthesized
Hypothyroidism effects
Lethargy, dec body temp, slowed respiration, low HR
Presygotic mechanisms of speciation
Pre: prevent formation of zygote completely -Temporal behavioral reproductive genetic isolation
G0 stage
Cell not carrying out functions in preparation for division
Anaerobes
Do not require oxygen by using fermentation for metabolism
Ovulation
Eventually estrogen reaches concentration threshold that results in positive feedback of GnRH, LH, FSH to spike
- Surge in LH induces ovulation
- Release of ovum from ovary into peritoneal cavity
Hypodermis def
subcutaneous layer below dermis
Induction
Process of groups of cells to influence nearby cells
-Ensures different cell types work together within an organ
3rd trimester
Continued rapid growth
-more brain development
antibodes transported from mother to fetus
-Growth rate slows and fetus is less active because less room
Retrovirus mechanism
DNA integrates into host cell genome and is replicated/transcribed
- Cell is infected indefinitely
- Only way to remove infection is to kill cell
Pluripotent stem cells
Can differentiate into any cell type not in placental structures
-After formation of the three germ layers
How do viruses reproduce?
Cannot reproduce independently
- Obligate intracellular parasites
- Must express and replicate genetic info within host cell
- Replicate and produce virions to infect additional cells
Role of blastocyst in fertilization
- Secretes hCG -> analog of LH
- Maintains corpus luteum
- Critical during 1st trimester
What results from fertilization
Zygote develops into blastocyst and implants into uterine lining
Pulmonary Respiration is -____
gas exchange in alveoli
Translocation Chromosomal mutations
Segment of DNA from one chromosome swapped with a segment of DNA from another
Autocrine signals
signals act on same cell that secreted the signal
What is the first checkpoint of the cell cycle and during what phase is it locarted?
End of G1 phase
-Checks if cell is ready to commit to cell division and replicate DNA
Trachea Composition
Contains hyaline cartilage
Has pseudostratified columnar epithelial cells
Also contains goblet cells
Vas deferens
Layer of muscle that regulates temp of sperm development
How does the pineal gland know to release melatonin
Receives projections from retina by responding to intensity of sunlight
Prophase
Condensation of chromatin into chromosomes
- Centrioles pair and separate to opposite side of cell
- Centrioles begin to form spindle finbers
Simple columnar epithelium
Nonciliated: More secretion and absorption than cuboidal
-GI tract -> stomach, gallbladder, ducts of glands
Ciliated: Moves particles away
-Bronchioles of respiratory tract, uterine fallopian tube
Microtubules
Hollow polymers of tubulin proteins
-Primary pathway for motor proteins like kinesin and dynein to carry vesicles
Three layers of wall of heart
Epicardium, myocardium and endocardium
Gene pool def
All alleles that exist within a species
-New genes added via mutations or gene leakage
What are cycline
Bind to cyclin-dependent kinases CDKs that can phosphorylate transcription factors’
-Promote transcription of genes required for the next cell cycle
Anaphase
Centromeres split so each chromitd has own centromere
-Sister chromatids separate -> pulled to opposite sides
Stabilizing selection def
Keeps phenotypes within specific range by selecting against extremes
Ex: gestational weight can’t be too much or too little
Stem cells
Cells not yet differentiated or that give rise to other cells that will differentiat
Tissue
Group of cells with common function that carry out specialized activities
List the 5 strata of the epidermis in order from deepest to shallowest
Stratum basale Stratum spinosum Stratum granulosa Stratum lucidum Stratum corneum
Who discovered transformation in bacteria
Griffith experiement -> frederick griffith
Bowman’s capsule definition
Encases glomerulus leads to PCT
Aldosterone kidney pathway
- Dec BP -> renin released from juxtaglomerular cellls
- Renin cleaves angiotensinogen to form angiotensin I
- Angiotensin-convertin enzyme metabolizes angiotensin I to angiotensin II
- Angiotensin II promotes release of aldosterone form adrenal cortex
- Aldosterone inc Na+ reabsorption in DCT and water reabsorption in collecting duct
- Aldosterone also inc K+ and H+ excretion
Bone Tissue
Support, protection, storage
- Houses blood forming tissues
- Exc. Matrix: calcified
Structural components of flagella
Filament, basal body, hook
What mutations are larger scale than nucleotide mutations
Chromosomal mutations
-Affects large segments of DNA
Renal hilum
Deep slit in center of medial surface of kidney
Treatment for type I diabetes
Regular injections of insulin required
Functions of TSH
- Set basal metabolic rate -> T3 and T4
2. Promote calcium homeostatsis -> Clacitonin release
Neo darwinism inclusive fitness
Inclusive fitness: measure of organism’s success in populations based on number of offspring, success in supporting those offspring, ability of offspring to support others
- Darwin did not look at behaviors of population in relation to protecting offspring
- this includes parents nature of endangering self to protect offspring
What chromosomes determine 23rd Choromosomes
Biological sex
What happens during fertilization to secondary oocyte?
Undergoes meiosis II and splits into mature ovum and another polar body
-Consists of large quantities of cytoplasm and organelles
Inbreeding depression def
Loss of genetic variation may cause reduced fitness of a population
Endoderm
Innermost layer
-Epithelial linings of digestive and respiratory tracts, pancreas, thyroid, bladder parts of liver
How long are cells usually in interphase?
For about 90% of the time
Basal body (flagella)
Anchors flagellum to cytoplasmic membrane and is motor for flagellum
What happens when blood osmolarity is high
Water reabsorption inc and solute excretion inc
Errector pilli function
Contract and cause hairs on skin to stand up
-Traps layer of heated air near skin
Pulmonary Ventilation is _____
Breathing
Codominance def
When more than one dominant allele exists for a given gene
Levels of human chorionic gonadotropin hCG
- Levels decline during 2nd trimester bc placenta sufficient in size to secrete prog/estro by itself
- Inhibited by high levels of prog/estro
Cell Junctions:
Hold individual cells together
-Contact point between plasma membrane of neighboring cells
Where do renal arteries, renal veins and ureters enter and exit kidney?
Through the renal hilum
What type of muscles line the bladder and what division of nervous system controls them
Detrusor muscles and are controlled by parasympathetic activity
Postzygotic mechanisms of speciation
ALlow for gamete fusion but lead to nonviable/sterile offspring
Hybrid invariability
Hybrid sterility
Hybrid breakdown
Anaphase I
Homologous chromosomes pulled to opposite pulls via disjunction
-Explain’s Mendel’s 1st law that each chromosome of paternal origin separates from its homologue of maternal origin
Example of tropic hormone pathway
GnRH and LH don’t directly induce change
-Make gonads release testosterone in males
What dynamics do expressivity and penetrance reflect?
Expressivity reflects genetics at an individual level
Penetrance: population level
What is the countercurrent miltiplier system in kidneys
Flow of filtrate in loop of Henle oposite direction from flow of blood in vasa recta
-Filtrate constantly exposed to hypertonic blood -> maximal reabsorption of water
Distal convoluted tubule function
Responds to aldosterone which promotes Na+ reabsorption
-Waste product secretion like PCT
Nervous Tissue
Neurons + Neuroglia: Contact nerve impulses
- Brain, spinal cord, nerves
- Neurons & muscle cells are excitable
Function of hormones
Bind to receptors of tissues and induce changes in gene expression or cellular functioning
What type of blood carried in pulmonary venules/arterioles?
Pulmonary arteriole: deoxygenated blood -> blood coming from heart to lungs
Pulmonary Venule: Oxygenated blood from lungs to the heart
Effect of parathyroid hormones
Dec excretion of Ca by kidneys, inc abosrption by Ca in gut
-Also promotes phosphorus homeostatsis by inc resorption of phosphate of bone and reduced reabsorption of phosphate in kidneys
Stratum spinosum def
Conencted to each of the other strata
Determination stage of cell specialization
Cell irreversibly commits cell to a specific lineage
Convergent evolution def
Independent developkent of similar characteristics in two or more lineages not sharing a common ancestor
-Analagous structures
Ex: fish and dolphins resemble each other but from different classes of vertebrates
What hormones increase reabsorption of water
aldosterons and ADH
When does transduction occur in the lysogenic cycle?
If extracts portions of bacterial DNA when leaving
What do cells of Leydig do
Secretes testosterone and other male sex hormones (androgens)
What tissue is hypodermis composed of
Connective tissue connnects it to skin and rest of body
-Composed of fat and fibrous tissue
Ex of selective transcription
Pancreatic islet cell has genes on to produce hormones but other cells would have these genes turned off
Cortex vs medulla of kidney location
Cortex: outermost
Medulla: within cortex
Telophae I
Nuc membrane reforms, each chromosome still has two sister chromatids at centromere
-Cells are now haploid
Species def
Largest group of organisms capable of breeding to form fertile offspring