dna

Question 1

nucleotide

Answer 1

monomer of nucleic acid

Question 2

What are the components of a nucleotide?

Answer 2

Pentose sugar, phosphate plus organic base which contains nitrogen.

Question 3

pentose sugar in dna vs rna

Answer 3

dna=deoxyribose
rna=ribose

Question 4

nucleotide bases are either

Answer 4

purine(two rings)
pyrimidine(one ring)

Question 5

pyrimidine bases

Answer 5

thymine
cytosine
uracil(rna)

Question 6

purine bases

Answer 6

adenine
guanine

Question 7

how are nucleotide bases linked to other molecules

Answer 7

by condensation reactions to form polymers

Question 8

dna structure

Answer 8

composed of 2 chains linked by base pairs which are complementary
forms a double helix which is only 2nm in diameter

Question 9

in a chromosome how long is dna

Answer 9

85mm long

Question 10

dna antiparallel

Answer 10

one srand goes from 5’ to 3’, another goes from 3’-5’, this makes the double helix

Question 11

functions of dna

Answer 11

replication- has two complementary strands; if two separate 2 more form and each is a template
protein synthesis-sequence of bases represents dna info and determines aa sequence

Question 12

cell division , daughter cell

dna replication allows

Answer 12

accurate copying for cell division, each daughter cell has an exact copy of genetic info

Question 13

semi conservative replication

Answer 13

dna is unwound and nucleotides are separated by dna helicase
nucleotide opposite complementary bases on template, hydrogen bonds form and nucleotides link by dna polymerase
each replica is a hybrid of parent and new strand

Question 14

meselson and stahl

Answer 14

ecoli cultured in 15n and amino acids providing evidence for semi conservative replication

Question 15

meselson and stahl first gen

Answer 15

dna produced 14n and 15n as it divided once
band produced of a mixture of 14 and 15, but rose a bit because of this

Question 16

meselson and stahl second gen

Answer 16

two bands produced as the relative abundance of the 14n increases

Question 17

meselson and stahl third and fourth gen

Answer 17

lighter band gets stronger
hybrid band gets fainter

Question 18

DNA is a store of

Answer 18

genes, genetic info coded into bases

Question 19

how does amino acid sequence determine characteristics of an organism

Answer 19

sequences direct amino acids which determine proteins and enzymes which direct reactions which make up characteristics of an organism

Question 20

dna is a triplet code

Answer 20

it comes in 3s which code foe specific amino acids

Question 21

how many dna codes are possible

Answer 21

4^3= 64

Question 22

dna code is non overlapping

Answer 22

each base only is in one triplet, and you read it separately

Question 23

dna code is degenerate

Answer 23

more than one triplet can encode each amino acid

Question 24

dna code is unambiguous

Answer 24

same codon does not code for 2+ amino acids

Question 25

dna code is universal

Answer 25

all organisms have the same triplet codes

Question 26

dna code is punctuated

Answer 26

there are 3 codons not for amino acids but for STOP CODONS

Question 27

codons vs triplet of bases

Answer 27

codons is in mrna triplet of bases is in dna

Question 28

exons

Answer 28

regions of dna that code for proteins/are expressed

Question 29

introns

Answer 29

regions of non coding dna that contain blocks of repeated nucleotides

Question 30

mrna function

Answer 30

transcribes instructions in dna and carries these to ribosomes

Question 31

trna

Answer 31

clover shape, provides linkage between mrna and amino acids transfers amino acids to ribosomes

Question 32

most prokaryotes are continuous

Answer 32

they have no introns/non coding sequences their entire gene is transcribed and translated

Question 33

one gene one polypeptide argument

Answer 33

one gene can have a variety of polypeptides because various exons produced by splicing can be cut and stuck in many ways

Question 34

gene

Answer 34

portion of dna that codes for a polypeptide chain

Question 35

post translational modification

Answer 35

modification of a polypeptide- can be modified by combination with non proteins

Question 36

carbohydrates lipids phosphates

Answer 36

glycoproteins lipoproteins phospho-proteins

Question 37

example of post translational modification

Answer 37

haemoglobin has secondary, tertiary and quaternary structure