Biology:4dna - dna and genes

Question 1

what does it mean when genetic code is universal
non overlapping
degenerate

Answer 1

universal - same triplet codes for the same amino acid in every organism

non-ovelapping - each base in the triplet is only read once

degenerate - multiple codons code for the same amino acid

Question 2

name the 3 structural features of a prokaryote DNA and where its found

Answer 2

circular
short
no histones
found in cytoplasm

Question 3

name the 3 structural features of a eukaryotic DNA and where its found

Answer 3

linear
long
hitones
found in nucleus

Question 4

state how hitones turn into dna(4 things)

Answer 4

they condense and coil into chromatin

chromatin coil into chromatids

chromatids replicate and form chromosomes

DNA then condenses to fit in nucleues

Question 5

what is a locus and what are homologous genes

Answer 5

locus is the location of the gene

homologous is the chromosomes you inherited from your parents

Question 6

name the 4 structural features of mrna
is it a codon or and anticodon

Answer 6

(transfer genetic code to ribosomes)

linear shape
its long
is a codon

Question 7

name the 4 structural features of trna
is it a codon or and anticodon

Answer 7

(transports amino acids to ribosomes)

clover shape
shorter
contains hydrogen
contains an amino acid binding site
anticodon

Question 8

how do we calculate ph

Answer 8

• log10(h+)

Question 9

name the b^x rule when calculating ph

Answer 9

if b^x = y
then logb(y) = x

Question 10

what goes on in transcription

Answer 10

dna helicase breaks hydrogen bonds between dna strands

complementary rna nucleotides move into place and form hydrogen bonds between bases on exposed nucleotides

rna polymerase joins together rna nucleotides by forming phosphodiester bonds

pre - mrna is produced

mrna leaves DNA and DNA goes back to normal double helix structure

mRNA enters cytoplasm

Question 11

what does splicing do

Answer 11

removes introns from mrna

Question 12

how does transcription stop

Answer 12

by a stop codon which affects rna polymerase

Question 13

what goes on in translation

Answer 13

ribosome binds to mrna at the start codon

trna with anticodon that is complementary to start codon binds
(held together by hydrogen bonds)

process repeats but on the next codon

peptide bond is formed(uses energy from atp)

ribosome moves to the next codon and the process repeats however the first trna is released

the process repeats forming polypeptides

stops when it reaches a stop codon

Question 14

name the 3 genetic mutation

Answer 14

deletion - one or more bases being removed causing frame shift

substitution - a base being swapped

insertion - a base being added causing a frame shift

Question 15

whats the difference between the two stages of mitosis

Answer 15

prophase 1 homologous chromosomes condense - propahse 2 chromosomes condense

telophase 1 2 daughteer cells are formed - telophase 2 - 4 daughter cells are produced

anaphase 1 - homologous chromosomes oulled apart - anaphase 2 chromatids pulled apart

Question 16

2 ways of variation in meisosis

Answer 16

crossing over - parts of chromosomes from parents are swapped

independent segregation - operating chromosomes into random combinations