07 cell cycle

what are the 4 types of bases in dna

adenine

thymine

cytosine

guanine

what are purines

adenine

guanine

what are pyrimidines

thymine

cytosine

where does transcription take place

nucleus

what is the structure of dna

stores rna, protein encoding info, transfers info to daughter cells

double stranded

deoxyribose as sugar

t, c, a, g

what is the structure of rna

carries protein encoding info, helps make proteins

single stranded

ribose as sugar

u, c, a, g

what are the 3 steps of transcription

initiation → rna polymerase (enzyme) uses dna as template to form complementary rna

elongation & termination → rna polymerase stops transcribing once it sees transcription termination signal in dna

transcription & splicing

where does translation take place

cytoplasm

what are the 2 steps involved in translation

initiation → ribosome scans mrna looking for start codon (methionine, aug)

elongation → terminates when ribosome hits stop codon (uga, uag, uaa)

what are chromosomes

one long piece of double-stranded dna that is inherited

how many chromosomes are there in a normal human cell

46

what is a diploid cell

46

what is a haploid cell

23

what are the 5 cell cycle phases

interphase

prophase

metaphase

anaphase

telophase

what are the 3 phases in interphase

g1 phase

s phase

g2 phase

what happens during g1 phase

growth & normal cellular activity

what happens during s phase

dna replication

6-8hrs

what happens during g2 phase

brief final prep for cell division

3-4hrs

what are the 2 phases in prophase

early prophase

late prophase

what happens during early prophase

centrioles divide

chromosomes condense & become visible

what happens during late prophase

nuclear envelope breaks down

nucleolus disappears

centrioles move to opposite poles

what happens during metaphase

chromatid pairs arranged on spindle equator

spindle is fully formed

what happens during anaphase

chromatids split at centromere

single chromatids pulled to opposite poles by contraction of spindle fibres

what happens during telophase

decondensation of chromatin

reformation of nuclear envelope

nucleolus disappears

what are the 8 steps involved in dna replication

1. helicase binds to origin & separates strands

2. bind proteins keep strands apart

3. primase makes short stretch of rna on dna template

4. dna polymerase adds dna nucleotides to rna primer

5. dna polymerase proofreading activity checks & replaces incorrect bases

6. continuous strand synthesis continues in 5' to 3' direction

7. discontinuous synthesis produces okazaki fragments on 5' to 3' template

8. enzymes remove rna primers, ligase seals sugar-phosphate backbone

what are telomeres

name given to end of each dna strand/chromosome

what are synonymous (silent) mutations

does not change amino acid

what are nonsynonymous (missense) mutations

DOES change amino acid

what are nonsynonymous (nonsense) mutations

intro STOP codon

what are insertion & deletion mutations

create frameshifts leading to STOP codons