3.4.1 + 3.4.2 DNA + proteinsynthesis

Question 1

similarities between eukaryotic DNA and prokaryotic DNA

Answer 1

nucleotide structure is identical
nucleotides are joined by phosphodiester bonds

Question 2

differences between eukaryotic DNA and prokaryotic DNA

Answer 2

eukaryotic is linear, prokaryotic is circular
eukayrotic is bound by histones prokaryotic is not
eukaryotic contains introns prokaryotic does not
eukaryotic is longer

Question 3

gene

Answer 3

section of DNA that codes for a polypeptide

Question 4

locus

Answer 4

position of a gene on a DNA moleucle

Question 5

triplet

Answer 5

sequence of 3 DNA bases which code for a specific amino acid

Question 6

universal

Answer 6

same specific base triplets code for the same amino acid in all living things

Question 7

non-overlapping

Answer 7

base triplets dont share bases, each base is read once

Question 8

degenerate

Answer 8

most amino acids are coded for by more than one base triplet

Question 9

start and stop codon

Answer 9

start codon: base triplet at the start of mRNA that signals the start of translation
stop codon: base triplet at the end of mRNA that signals the end of translation

Question 10

intron

Answer 10

parts of DNA within a gene that do not code for a polypeptide

Question 11

exons

Answer 11

parts of DNA within a gene that code for a polypeptide

Question 12

genome

Answer 12

complete set of genes in a cell

Question 13

proteome

Answer 13

all the proteins a cell is able to produce

Question 14

structure of mRNA

Answer 14

single stranded copy of a gene
contains uracil instead of thymine

Question 15

structure of tRNA

Answer 15

single stranded
clover leaf shape with hydrogen bonds between specific base pairs
anticodon region which binds to condons on mRNA
specific amino acid binding site

Question 16

transcription

Answer 16

occurs in the nucleus
1. DNA helicase breaks the hydrogen bonds between the two DNA strands
2. the strands unwind exposing the bases
3. 1 DNA strand acts as the template, free RNA nucleotides line up across the template strand according to complementary base pairing
4. RNA polymerase joins the nucleotides together until the stop codon is reached
5. pre-mRNA undergoes splicing, removing the intron sections
6. mRNA leaves through the nuclear pores

Question 17

translation

Answer 17

occurs in the ribosome
1. mRNA attaches to the ribosome at the start codon
2. t RNA with an anticodon attaches to the start codon (the codon and anticodon are complementary to eacother)
3. a second tRNA moleucle attaches to the second codon
4. tRNA carry a specific amino acid determined by their anticodon
5. adjacent amino acids are joined together in a condensation reaction forming a peptide bond, using ATP
6.tRNA is released after the amino acid joins the polypeptide
7.ribosome moves across mRNA forming a polypeptide chain until it reaches the stop codon

Question 18

why is ATP needed during proteinsynthesis

Answer 18

to provide energy for the bond between tRNA and the amino acid
to provide energy for the formation of the peptide bond

Question 19

how can a change in the DNA sequence result in a change in the structure of the protein

Answer 19

it change the primary structure, changing the hydrogen bonding in the secondary structure changing the 3D structure of the tertiary structure

Question 20

how does a gene code for a protein

Answer 20

genes consist a sequence of bases, each 3 bases - triplets - code for 1 amino acid, therfore the order of bases determines the sequence of amino acids = primary structure