Quicksheet: Biology

law of segregation

homologous alleles (CHMs) separate so that each gamete has one copy of each gene (either P (purple) or p (white))

law of independent assortment

alleles of unlinked genes assort independently in meiosis (AB, Ab, aB, ab)

patterns of inheritance

• autosomal recessive

• autosomal dominant

• x-linked (sex-linked)

autosomal recessive

may skip generations

autosomal dominant

appears in every generation

x-linked (sex-linked)

no male-to-male transmission, and more males are affected

nucleic acid basic unit

nucleotide: sugar, nitrogenous base, phosphate

DNA’s sugar vs RNA’s sugar

deoxyribose vs ribose

2 types of bases

double-ringed purines (adenine, guanine)

single-ringed pyrimidines (cytosine, uracil, thymine)

DNA double helix vs RNA strand

antiparallel strands joined by base pairs (A=T, G=C)

single stranded, A=U (not T)

who is transcriptional regulation done by? what regulates it?

prokaryotes

operon

structural genes

have DNA that codes for protein

operator genes

repressor binding site

promoter gene

RNA polymerase’s 1st binding site

inducible system vs repressible system

need an inducer for transcription to occur vs. need corepressor to inhibit transcription

point mutation

one nucleotide is substituted by another; silent if the sequence of AA doesn’t change

frameshift mutations

insertions or deletions DNA bases in numbers not divisible by three

proteins doesn’t form/nonfunctional

viruses

acelular structures of double- or single- stranded DNA or RNA in a protein coat

lytic cycle vs lysogenic cycle

virus kills the host cell vs virus enters host genome

plasmid vs episome

extragenomic material; replicates independently

plasmid that can be integrated into the genome; replicated alone w/ genome

three types of genetic exchange

transformation

conjugation

transduction

transformation

bacterium acquires a piece of genetic material from environment and integrates genetic material into host cell genome (ex: antibiotic resistance)

conjugation

bacterial form of mating using bridge of sex pilli which are formed using plasmids (sex factors)

transduction

bacteriophage acquires genetic information from a host cell (ex: some genetic material from host cell packaged w/ viral genetic material and transferred to other host cell)

alleles

alternative forms of a gene

• dominant: needs one copy to be expressed

• recessive: needs 2 copies to be expressed

genotype

combination of alleles at a given genetic locus

• homozygous: two of same allele

• heterozygous: two different alleles

• hemizygous: only one allele (male XY chm)

silent mutation

no effect on protein

missense mutation

substitution of one AA for another

nonsense mutation

substitution of a stop codon for an AA

insertions/deletions

result in a shift in reading frame, leading to changes for all downstream AAs

nucleus

contains all genetic material necessary for replication of cell

mitochondrion

-pyruvate dehydrogenase, Kreb cycle, ETC, oxidative phosphorylation, ATP production occur here

lysosome

membrane bound-structure containing hydrolytic enzymes capable of breaking down many different substrates

RER

site of synthesis of proteins destined for insertion into membrane or secreation

SER

lipid synthesis and detoxification occurs

Golgi apparatus

posttranslational modification of proteins

peroxisomes

contains hydrogen peroxide

site of beta-oxidization of very long chain of fatty acids

Cell division cycle

G1: cell inc. in organelles and cytoplasm

S: DNA replication

G2: same as G1

M: cell divides in two

four stages of early development

-cleavage: mitotic division w/out inc. overall size

-gastrulation: blastula forms three distinct primary germ layers: ecoderm, endoderm, mesoderm

-neurulation: precursor to central nervous system

-organogenesis - germ layers differentiate

ectoderm

nervous system, epidermis, lens of eye, inner ear (“attract” oderm)

endoderm

lining of digestive tract, lungs, liver and pancreas (“endernal” organs)

mesoderm

muscles, skeleton, circulatory system, gonads, kidney (“means” oderm)

cell body (soma)

location of nucleus as well as organelles such as endoplasmic reticulum and ribosomes

dendrites

appendages that receive signals from other cells

schwann cells

-insulate nerve fibers (axons) by forming fatty myelin sheaths

-provide nutrients and aid in ner regeneration

nodes of ranvier, myelin sheath

-unmyelinated gaps packed with voltage-gated ion channels; allows signal to jump from node to node

-insulating, fatty layer; speed up nerve signals

axon

long appendage down which an action protential travels

nerve terminals/synaptic bouton

end of axon from which neurotransmitters are released

resting potential

-high [Na+] outside cell; hight [K+] inside cell by Na+/K+ ATPase

-mvmnt of ions down [] gradient through leak channels est. this

action potential

stimulus acting on the neuron, depolarizing the membrane of the cell body

impulse propagation

depolarization (Na+ rushing into axon) followed by repolarization (K+ rushing out of axon) along the nerve axon

the synapse

-voltage-gated Ca2+ channels open; Ca2+ into cell

-vesicles fuse w/ presynaptic mem sending NT across synaptic cleft

-NT binds to receptor on postsynaptic mem, triggering depolarization

neuron at rest

all gates closed

depolarization

Na+ gates open

Repolarization

Na+ gates inactivate; K+ gates open

Hyperpolarization

K+ channel gates are closing

Follicle-stimulating (FSH)

anterior pituitary

stimulates follicle maturation; spermatogenesis

Luteinizing (LH)

anterior pituitary

stimulates ovulation; testosterone synthesis

adrenocorticotropic (ACTH)

anterior pituitary

stimulates adrenal cortex to make the secrete glucocorticoids

thyroid-stimulating (TSH)

anterior pituitary

stimulates the thyroid to produce thyroid hormones

prolactin

anterior pituitary

stimulates milk production and secretion

endorphins

anterior pituitary

inhibits the perception of pain in the brain

growth hormone

anterior pituitary

stimulates bone and muscle growth/lipolysis

oxytocin

hypothalamus; stored in posterior pituitary

stimulates uterine contractions during labor, milk secretion during lactation

antidiuretic (ADH, vasopressin)

hypothalamus; stored in posterior pituitary

stimulates water reabsorption in kidneys

thyroid hormones (T₃, T₄)

thyroid

stimulates metabolic activity

calcitonin

thyroid

decreases (tones down) blood calcium levels

parathyroid hormone

parathyroid

increases blood calcium levels

glucocorticoids

adrenal cortex

inc. blood glucose level and dec. protein synthesis'; anti-inflammatory

mineralocorticoids

adrenal cortex

inc. sodium and water reabsorption in kidneys

epinephrine, norepinephrine

adrenal medulla

inc. blood glucose level and heart rate

glucagon

pancreas

stimulates conversion of glycogen to glucose in the liver; inc. blood glucose

insulin

pancreas

lowers blood glucose; increases glycogen stores

somatostatin

suppresses secretion of glucagon and insulin

testosterone

testes

maintains male secondary sex characteristics

estrogen

ovary/placenta

maintains female secondary sex characteristics

progesterone

ovary/placenta

promotes growth/maintenance of endometrium

melatonin

pineal

regulates sleep-wake cycles

atrial natriuretic peptide

heart

involved in osmoregulation and vasodilation

thymosin

thymus

stimulates T-cell development

sarcomere

-contractile unit of the fibers in skeletal muscle

-contains thin actin and thick myosin filaments

humoral immunity (specific defence) - active vs. passive

-a: AB are produced during an immune response

-p: AB produced by one organism are transferred to another orgnaism

humoral immunity components

B-lymphocytes (WBC)

• memory cells

• plasma cells

memory cells

remember antigen, speed up secondary response

plasma cells

make and release AB, which induce antigen phagocytosis

• AB: IgG, IgA, IgM, IgD, IgE

cell-mediated immunity (specific defense) components

T-lymphocytes (WBC)

• cytotoxic T-cells

• helper T-cells

• suppressor T-cells

• memory cells

cytotoxic T-cells

destroy cells directly

helper T-cells

activate B- and T- cells and macrophages by secreting lymphokines

suppressor T-cells

regulate B- and T- cells to decrease anti-antigen activity

nonspecific immune response

includes skin, passages lined with cilia, macrophages, inflammatory response, and interferons (proteins that help prevent the spread of a virus)

three portal systems

blood travels through an extra capillary bed before returning to heart

• liver (hepatic), kidney and brain (hypophyseal)

contraction - initiation

depolarization of neuron leads to an action potential

contraction - sarcomere shortening

-sarcoplasmic reticulum releases Ca2+

-Ca2+ binds to troponin on actin filaments

-tropomyosin shifts, exposing myosin-binding sites

-myosin binds, ATPase activity allows myosin to pull thin filaments towards the center of H zone, then ATP causes dissociation

contraction - relaxation

Ca2+ pumped back into the sarcoplasmic reticulum

fluid mosaic model

• phospholipid bilayer with cholesterol and embedded proteins

• Exterior: hydrophilic phosphate head grps

• interior: hydrophobic fatty acids

cell theory four basic tenants

-all living things are composed of cells

-the cells is the basic functional unit of life

-cells arise only from preexisting cells

-cells carry genetic info (DNA)

three prokaryotic shapes

-cocci: spherical

-bacilli: rod-shaped

-spirilli: spiral-shaped

histone proteins

what DNA is wound around in eukaryotes to form nucleosomes

• H2A, H2B, H3, H4

chromatin

DNA and its associated histone

heterochromatin vs euchromatin

dense, transcriptionally silent DNA vs less dense, transcriptionally active DNA