DNA and protein synthesis

Question 1

what is DNA wound around in eukaryotes

Answer 1

histone proteins

Question 2

which other sub-cellular structures contain DNA

Answer 2

mitochondria and chloroplasts

Question 3

what is mitochondria and chloroplast DNA like

Answer 3

prokaryotic DNA as its circular and shorter

Question 4

how is DNA found in prokaryotes

Answer 4

shorter and circular and not wound around histones

Question 5

define what a gene is

Answer 5

a sequence of DNA bases that codes for a polypeptide or functional RNA

Question 6

what does the sequence of polypeptides form

Answer 6

primary structure of protein

Question 7

how many amino acids code for a gene

Answer 7

3

Question 8

define genome

Answer 8

the complete genetic makeup of a cell

Question 9

define proteome

Answer 9

the full rage of proteins that a cell is able to produce

Question 10

what is an intron

Answer 10

a section of a gene that doesnt code for amino acids

Question 11

what is an exon

Answer 11

the part of the gene that does code for amino acids

Question 12

what happens to introns during protein synthesis

Answer 12

they are removed so they dont affect amino acid order

Question 13

what type of DNA doesnt contain introns

Answer 13

prokaryotic

Question 14

what is a non-coding repeat

Answer 14

a section of dna that is non coding and repeats over

Question 15

alleles coding for the same characteristic can be found where on a chromosome

Answer 15

a the same position

Question 16

what process is mRNA made in

Answer 16

transcription

Question 17

what is the job of mRNA

Answer 17

carries the genetic code from DNA to ribosomes where it makes protein

Question 18

what is the structure of mRNA

Answer 18

single polynucleotide strand

Question 19

what is a codon

Answer 19

3 adjacent bases

Question 21

what is the function of tRNA

Answer 21

carries the amino acids used to make proteins to ribosomes

Question 21

what is the structure of tRNA

Answer 21

single polynucleotide strand folded into a clover shape

Question 22

why does tRNA contain H bonds

Answer 22

between base pairs to help hold it in shape

Question 23

what is an anticodon

Answer 23

a specific sequence of three bases a the end of every tRNA molecule

Question 24

what are at both ends of tRNA

Answer 24

an anticodon and an amino acid binding site

Question 25

where does this mRNA then travel

Answer 25

out of the nucleus to the nuclear pore

Question 26

what then happens to the dna strand

Answer 26

hydrogen bonds reform and it goes back to double helix

Question 27

whats an intron

Answer 27

non coding region

Question 28

whats an exon

Answer 28

coding region

Question 29

what happens in splicing

Answer 29

Introns are removed and exons joined together

Question 30

where does splicing take place

Answer 30

in the nucleus

Question 31

what is the first step in translation

Answer 31

mRNA attaches to a ribosome and tRNA molecules carry amino acids to it

Question 32

what allows the tRNA to bond with the codon

Answer 32

it has anticodons which form h bonds with codons

Question 33

what will bond to the first tRNA

Answer 33

another one next to it which will form a peptide bond

Question 34

what does the two bonded tRNA then do

Answer 34

release the first and continue moving down

Question 35

what do gene mutations involve

Answer 35

a change in the DNA base sequence

Question 36

what is substitution

Answer 36

when one base is substituted with another

Question 37

what is deletion

Answer 37

when one base is deleted

Question 38

what does the degenerate code of DNA mean

Answer 38

some amino acids are coded for by more then one dna triplet

Question 39

what does the degenerate code of DNA mean for substitution of amino acids

Answer 39

not all result in a change of the amino acid sequence

Question 40

what type of mutation will always lead to changed of amino acids

Answer 40

deletion

Question 41

what might increase the rate of mutations

Answer 41

UV radiation radiation and some viruses

Question 42

What is a locus

Answer 42

Particular position where gene is fixed on a chromosome

Question 43

Name the 3 features of the genetic code

Answer 43

Degenerate Universal Non-overlapping

Question 44

What is non disjunction

Answer 44

When chromosomes or chromatids do not split equally during anaphase

Question 45

What is polyplody

Answer 45

Changes in whole sets of chromosomes meaning u have two or three sets of chromosome

Question 46

What is aneupolidy

Answer 46

Changes in number of individuals chromosomes

Question 47

What does aneuploidy usually result in

Answer 47

Having one more of one fewer chromosomes 

Question 48

What 2 main factors lead to variation in meiosis

Answer 48

Independent segregation of homologous chromosomes. Crossing over between homologous chromosomes.

Question 49

How can cpu calculate the possible combinations of chromosomes

Answer 49

2n N = number of homologous pairs

Question 50

Describe two differences between the structure of tRNA molecule and the structure of mRNA molecule

Answer 50

tRNA has a clover like shape, where are is mRNA is linear TRNA has anticodons at either end, where is mRNA codons only

Question 51

Describe the differences between pre-mRNA and mRNA

Answer 51

Pre-mRNA contains entrance, where as Emani doesn’t. A splicing occurs in pre-mRNA, which removes introns

Question 52

Describe how One amino acid is added to a polypeptide that has been formed at a ribosome during translation.

Answer 52

TRNA brings a specific amino acid. an anti codon bonds with the codon As this is repeated the base bind together, forming a peptide chain

Question 53

Describe how mRNA is produced from an expose template strand of DNA

Answer 53

Free, RNA nucleotides form complimentary base pairs Phosphodiester bonds form. By RNA polymerase. 

Question 54

Name the steps of transcription

Answer 54

Dna helix unwinds One chain of dna will act as a template Winding an unzipping is caused by DNA helicase Dna helicase breaks the hydrogen bonds Free mRNA nucleotides align to complementary bases Enzyme RNA polymerase bonds RNA nucleotides

Question 55

Explain the translation process

Answer 55

MRNA attaches to a ribosome in nucleus Ribosome attaches to start codon Complementary anticidon aligns with start codon Ribosome moves along mRNA Amino acids joined by tRNA

Question 56

give one way the structure of an mRNA molecule is diff from a trna molecule

Answer 56

mRNA is linear wheras tRNA is clover shaped

Question 57

explain the difference between pre-mRNA and mRNA

Answer 57

pre-MRNA contains introns and exons whereas mRNA only contains exons

Question 58

how is mRNA produced in the nucleus of a cell

Answer 58

- DNA helicase breaks hydrogen bonds - one strand is used as template - free floating nucleotides bind with complementary bases on template strand - rna polymerase joins nucleotides pre- mrna sliced to remove introns

Question 59

why is the genetic code described as universal

Answer 59

same triplet codes for same amino acids

Question 60

how does a mutation to a tumor suppressor gene result in a tumour?

Answer 60

- tumour suppressor gene inactivated - so rate of cell division too fast

Question 61

explain how cell fractionation and ultracentrifugation can be used to isolate mitochondria

Answer 61

1- break open cell 2- filter to remove debris 3- use isotonic solution to prevent damage to mitochondria 4- keep cold to reduce damage to enzymes 5-centrifuge at lower speed to reduce damage 6- respin to get mitochondria

Question 62

explain how cell fractionation and ultracentrifugation can be used to isolate mitochondria

Answer 62

1- break open cell 2- filter to remove debris 3- use isotonic solution to prevent damage to mitochondria 4- keep cold to reduce damage to enzymes 5-centrifuge at lower speed to reduce damage 6- respin to get mitochondria