genetics module Flashcards
somatic cells
non reproductive cells. have 2 sets of chromosomes. go through mitosis (example - muscle cells)
gametes
reproductive cells (sperm and egg) each have half a set of chromosomes
cytokinesis
process where the two cells physically split apart (is a process within both mitosis and meiosis) happens through cleavage furrow in animal cells and cell all in plant cells
G1 checkpoint
cell decides whether or not the cell is viable for continuing. checks for cell size, proper nutrients, proper growth and if there is damage
G0 phase
if the cell is not viable after G1 checkpoint it will enter this phase and either recover and return back to go through mitosis or stay in this phase
G2 checkpoint
checks for dna damage and problems with replication. if there is something wrong the cell will stop and fix the problem
spindle checkpoints
checks the chromosome attachment during mitosis. (whether all chromosomes have been attached for anaphase
what is the chemical constituent in nucleotides
nucleosides and a phosphate group
purines
A, G
pyrimidines
C, T, U
how are nucleotides held together
by a phosphodiester bond in a 3’ to 5’ orientation
binary fission
prokaryote reproduction by cell division. chromosomal reproduction starts at the origin of replication
autosomes
non sex chromosomes
prophase one
where crossing over occurs (only part of meiosis where this happens)
metaphase 2
homologous chromosomes line up to begin separation
metaphase 1
sister chromatids line up to begin separation
synapsis
loose pairing of homologous chromosomes during meiosis 1, and allows crossing over during prophase 1 and ensures match up of homologous chromosomes
semiconservative dna replication
breaking apart the double helix of dna in order to get 2 parent strands to use as a template for the new dna strands
transcription
converting dna into rna
translation
converting rna into proteins
enzyme/enzyme complex responsible for translation
ribosomes
enzyme/enzyme complex responsible for reverse transcription
rna dependent dna polymerase
euchromatin
loosely packed chromatin
heterochromatin
chromatin densely packed in the nucleus
pedigree analysis
determining if the person has a (increased) chance of certain diseases that develop later in life
promoter
dna sequence that rna polymerase attaches to in order to start translation
which way is dna strand made
3’ to 5’
which way is rna strand made
5’ to 3’
G-Cap
the way pre mRNA molecules are altered at the 5’ end end in eukaryotes
poly a- tail
eukaryotes pre mRNA molecules are altered at 3’ end (rna is make 3-5, poly tail modifies at the beginning)
introns
non coding regions of mRNA transcript
exons
coding regions of mRNA transcript
RNA splicing
removes introns and joins extrons
where does transcription occur in eukaryotes
nuclear envelope
where does transcription occur in prokaryotes
everything happens in the cytoplasm in prokaryotes
primary transcript
initial rna transcript from any gene prior to processing
triplet code
non overlapping nucleotide code for amino acids. contains 3 polypeptides
stop codes
UAA + UAG + UGA
indicator codons
AUG
reading frame
order of polypeptides to be produced
rna polymerase
pries dna strands apart and hooks rna nucleotides together
` dna polymerase
catalyzes elongation of new dna at replication fork. rate =500 nucleotides/second in bacteria and 50 nucleotides/second in humans
primer
dna polymerase needs a primer in order to begin catalyzing
helicase
uses energy (ATP) to break hydrogen bonds and separate the strand at the replication fork
semi discontinuous model
new nucleotides are added (via dna polymerase) contunuously from 3’ to 5’ only (this is not the true way)
leading strand
continuous synthetization of dna. moves ahead of the lagging strand
okazaki fragments
only on the lagging strand. are joined together by dna ligase
genetic counselling
identifying parents at risk of producing kids with genetic defects. higher in mothers over 35, and couples with recessive alleles
gene
one specific protein that can be a part of a long strand of dna
allele
variation among genes. two people can have the same gene but because they code for two different things, they are two different alleles.
synapsis
homologous chromosomes line up gene by gene on top of each other to get ready for crossing over (only happens during meiosis)
independent assortment
during meiosis chromosomes line up along the centrosome independent of each other and sort out independent of each other so they are in random order at the end of meiosis
crossing over
only during prophase 1. created genetic variation by crossing genes over with one another
random fertilization
any spend can fertilize any gene, creating genetic variation because one specific sperm does not always go for one specific ovum
true breeding
plants that can pollenate themselves are true breeders because they are breeding the same offspring every time
hybridization
crossing over two true breeding organisms, one being homozygous recessive and one homozygous dominant.
dihybrid cross
crossing two organisms that have the same genes for two traits. (one gene dom=brown hair rec=blonde hair, other gene dom=brown eyes, rec=blue eyes)
monohybrid cross
crossing two organisms both with only one gene.
P generation
parent generation of offspring. parent generation is true breeding and has self pollenated
F1 generation
p generations offspring after pollenating its self. the F1 generation will now also self pollenate (all heterozygous)
F2 generation
F1 generations offspring after self pollenating itself. (25% homozygous dom, 50% heterozygous, 25% homozygous recessive)
complete dominance
heterozygous individuals will show the same trait as homozygous recessive individuals. dominant trait will always show over recessive trait.
incomplete dominance
the heterozygous individual will show a mix between dominant and recessive genes.
codominance
both alleles of a gene will show their phenotypic trait. (like blood type)
pleiotropy
one gene can show more than one phenotypic trait (ex. one gene could show both eye color and hair color)
epistasis
one gene can effect whether another gene can have phenotypic expression or not. (baldness gene would be epistatic towards brown hair gene because you cannot have both)
