Nucleic Acids and Protein Synthesis

Question 1

describe DNA molecule (4)

Answer 1

made of two polynucleotide strands in opposite directions
held by hydrogen bonds
double helix
covalent and hydrogen bond present

Question 2

how does deoxyribose nucleic acid look like

Answer 2

phosphate group - ribose sugar - base

Question 3

what is needed for complementary base pairing

Answer 3

purine + pyramidine

Question 4

describe RNA (4)

Answer 4

ribonucleic acid
adenine + uracil
guanine + cytosine
single strands of polynucleotide

Question 5

which bases are purine

Answer 5

A/G

Question 6

which bases are pyramidine

Answer 6

T/C/U

Question 7

describe ATP

Answer 7

1/2/3 phosphate group + adenosine

Question 8

describe semi conservative replication of DNA (5)

Answer 8

DNA double helix unzips and hydrogen bonds break by enzyme helicase
nucleotides from nucleus with two phosphate groups = activated
bind complememtaru to base pairs on old DNA strand
DNA polymerase links phosphate and sugar groups
two extra phosphate groups go back to nucleus

Question 9

what is needed for semi conservative replication of DNA (3)

Answer 9

enzyme helicase
activated nucleotides
DNA polymerase

Question 10

why is it called semi conservative replication of DNA

Answer 10

one strand if the original DNA and other half is the new strand

Question 11

which comes first in protein synthesis

translation/transcription

Answer 11

transciption

Question 12

describe protein synthesis (10)

Answer 12

transcription:
strand of DNA unzipped by helicase in nucleus
hydrogen bonds break
complementary copy of gene (mRNA) made by RNA polymerase
mRNA leave through pore
translation:
mRNA attaches to ribosome in cytoplasm
mRNA reads code three bases at time on tRNA
codes for amino acid (triplet code)
tRNA anticodons bind to mRNA codons
peptide bond formed between amino acids to form polypeptide
stop codon at the end

Question 13

describe exocytosis (4)

Answer 13

Vesicle moves to the cell surface membrane
Fusion with membrane
Vesicle contents are excreted
ATP required

Question 14

describe sickle cell anemia mutation (6)

Answer 14

Base substitution;
Altered RNA codon;
Altered primary structure - quarternary structure;
Less soluble;
Stick together;
Less able to bind to oxygen;

Question 15

what are okazaki fragments (3)

Answer 15

DNA polymerase works in one direction
can only add activated nucleotides at 3’ end
DNA polymerase first binds to RNA primes
discontinuous replication happens on lagging strand