genetics 1

heritable traits

DNA→RNA→Protein→Trait

what do genes control?

changes to DNA

what does evolution occur through?

true

T/F: traits (including genetics) are only partially genetic

mutation

change in genetic sequence (usually DNA)

allele

specific version of a gene

genotype

set of alleles that an individual has

genome

alleles of every gene in an individual

phenotype

traits caused by genotype

sequence to make protein

thin/ thick

not protein coding info

thin

messenger RNA

thick

1

how many genes can affect many phenotypes?

by sequencing and comparing homologous genes/ entire genomes from different species

how can we use genetics to compare relatedness between species?

• understanding evolution of that species

• medical research

• general understanding of phenotypes

• paternity

• criminal forensics

how can we use genetics to compare relatedness within a species?

13

how many STRs are used for genetic profiling?

5-50

each STR has between how many possible alleles?

phosphate group, sugars, and bases

what are the 3 parts of nucleotides?

true

T/F: sugars and bases are a mix of nonpolar/ polar and the phosphate group is charged

inside

is the base on the inside or outside?

antiparallel

what direction do nucleic bases bind in?

false

T/F: always add new nucleotides to the 5’ end

• stable, but changeable

• hydrophilic- stable in water

• grooves allow access to the info

• regular predictable structure, regardless of which bases are present

• double stranded- 2 templates available to copy

what are properties of DNA double helix?

false

T/F: DNA replication doesn’t depend on its structure

true

T/F: the leading strand works smoothly

primase

synthesizing short RNA primer from DNA template

ligase

able to join 2 DNA fragments

lagging

is ligase only needed for the leading or lagging strand?

false

T/F: DNA can’t be modified

epigenetics

modification of DNA and chromosomes to change how they’re accessed

remodling proteins

what changes the chromosome structure?

true

T/F: if it’s more open, it’s easier to transcribe and if it’s more compact, its harder to use

mRNA

what is the 1 type of RNA that is translated?

• an RNA subunit of ribosomes

• extensive secondary structure determined by nucleotide sequence

• double stranded regions of stem-loops are anti-parallel

16S rRNA

true

T/F: transcription produces and RNA that is complementary and antiparallel to the template

true

T/F: only a localized region of the DNA is unwound by RNAP

RNA polymerase

makes an RNA copy from DNA

single

an RNA is produced from a single or double strand of DNA?

no

do genes normally overlap?

true

T/F: the template strand is always read 3’ to 5’

initiation, elongation, and termination

what are the 3 parts of transcription?

elongation

RNA polymerase doing its job

coding and noncoding

a transcriptional unit contains coding, noncoding, or both regions

promoter

RNAP binding site

terminator

site where RNAP releases from DNA and transcription is terminated

it bumps into random sequences

How does RNAP bind?

consensus

do promoters share an identical or consensus sequence?

true

sequence contributes to promoter strength by affecting affinity for the RNAP

true

promoter strength is a measure of the frequency of transcription initiation

• part of RNAP

• only prokaryotes use them

• can regulate specific genes

sigma factors

• creates physical force

• stem-loop makes polymerase stop

• breaks H bonds

• A-U weaker interaction from G-C

rho-dependent termination

modular

promoter sequences are ___

• regulatory promoter

• enhancer

• gene switch

• operator

what are the binding sites for transcription factors?

mediator

binds transcription factors and RNAP and mediates the interactions

in the nucleus

where does processing occur?

introns/ exons

(introns/exons) ___ must be removed and ___ spliced together

• prevents degradation in nucleus

• helps export RNA to cytoplasm

• promotes stability in cytoplasm

5’ cap

• at 3’ end

• helps export RNA to cytoplasm

• promotes stability in cytoplasm

polyA tail

remove parts of pre-mRNA that aren’t needed

splicing

splicesome

what does the splicing, mode of functional RNA, and only in eukaryotes? 

limites the invasion of foreign genes and censors the expression of their own genes

RNA interference

true

there are many types of small RNAs, and they must be processed to become functional

tRNAs

what brings amino acids to the ribosome?

aminoacyl-tRNA synthetases

what “charges” the tRNA?

Shine-Dalgarno

what positions the ribosome?

exit, protein, amino acid

what does EPA stand for?

a protein

what is the release factor?

in prokaryotes because no nucleus

where can coupled transcription and translation only occur in and why?

3rd

silent mutations mostly happen in what base?

false

T/F: if you add/ remove in an intron, there’s a change in the protein

it would stop

what would happen if you delete 3 bases in the promoter?

true

T/F: if you change the codon, it stays the same

true

regulation can occur at different levels of gene expression

true

T/F: often genes with a common function are transcriptionally linked

promotes txn

when the small molecule is present and is inducible, that means it…

blocks txn

when the small molecule is present and is repressible, that means it..

promotes txn

when the txn factor binds DNA, positive means that it…

block txn

when the txn factor binds DNA, negative means that it…

LacZ

beta galactosidase is the product of what structural gene?

LacY

permease is the product of what structural gene?

“acts in cis”

lacO affects transcription of the lac structural genes to which it is physically linked

“acts in trans”

lacI produces a soluble protein, thus it is not limited to acting on same DNA as lacI gene

true

partial diploids have 2 copies of some genes

false

T/F: lacO^c can bind repressor

lacP and lacO

what genes are binding sites?

the Lac Repressor

what protein/ binding site is a negative system?

LacZ^-

what allele doesn’t make a functioning protein?

the lac repressor

the lac operon is controlled by what?

the lac operon transcription by inhibiting lac repressor binding

the allosteric regulator induces what and how?

LacZ^- LacY^-

what are mutations of lac operons that are always off?

true

T/F: superrepressor mutants are always off; mutation that cannot bind “inducer”

lactose and glucose

is the lac operon regulated by lactose, glucose, or both?

cAMP-CAP

what activates lac operon txn?

cAMP

allosteric regulator of CAP and levels increase in low glucose

CAP is inactive due to low cAMP

bacteria prefer to use glucose as a food source

cAMP levels rise, so CAP can activate txn of genes for many catabolic pathways

in the absence of glucose, the bacteria will use whatever food source is available

allolactose inactivates lacI, cAMP activates CAP. Together they cause expression of the lac operon structural genes

if glucose is absent and lactose is available, then the bacteria will make the proteins needed to metabolize lactose

don’t

if glucose is present, do or don’t transcribe?

glucose

cells are responding to how much lactose or glucose is present?

false

T/F: if glucose is present, the CAP activator can bind

true

T/F: + glucose - lactose for RNAP to bind