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 shift reading frame; 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

plasmid that can be integrated into the 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 fo 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

-implantation: embryo implants during blastula stage

-gastrulation: ecoderm, endoderm, mesoderm

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)