DNA and Genetic Replication (7)

Question 1

what are dna and rna

Answer 1

nucleic acids

Question 2

what is the full name of Dna

Answer 2

deoxyribonucleic acid

Question 3

what is the full name of RNA

Answer 3

ribonucleic acid

Question 4

what does dna do simply

Answer 4

holds genetic information

Question 5

what does RNA do simply

Answer 5

transfers genetic information from DNA to ribosomes

Question 6

what are dna and rna polymers of

Answer 6

they are polymers of nucleotides

Question 7

who discovered the structure of DNA

Answer 7

watson and crick

Question 8

what is the structure of DNA

Answer 8

it consists of 2 polynucleotide strands joined together by hydrogen bonds to form a double helix

Question 9

what is in each DNA nucleotide

Answer 9

1) the pentose sugar deoxyribose

2) the phosphate group

3) one of 4 nitrogen containing bases (adenine, thymine, cytosine, guanine)

Question 10

what are the nucleotides in each polypeptide strand joined by and how

Answer 10

phosphodiester bonds formed by condensation reactions

Question 11

what forms the backbone of the polynucleotide strands

and why are bases oriented towards the centre

Answer 11

the pentose sugar and phosphate group

to protect them from reacting with other chemicals

Question 12

how is the structure of DNA relatively stable

Answer 12

the bases are joined by hydrogen bonds which individually are weak but due to their large number collectively maintain a stable structure

Question 13

how can dna helix provide an even more compact store of genetic information

Answer 13

the dna helix is further coiled to produce a super helix providing a compact store of genetic information

Question 14

what direction are the dna strands going in

Answer 14

anti parallel

Question 15

what direction are the dna strands going in

Answer 15

anti parallel

Question 16

how is the structure of DNA adapted for its function?

sugar phosphate backbone

Answer 16

provides stength

Question 17

how is the structure of DNA adapted for its function?

helix

Answer 17

gives compact shape

protects sequence of bases

Question 18

how is the structure of DNA adapted for its function?

double stranded

Answer 18

each strand serves as a template in replication

protects sequence of bases

makes molecule more stable

Question 19

how is the structure of DNA adapted for its function?

large molecule

Answer 19

large amount of genetic material can be stored

Question 20

how is the structure of DNA adapted for its function?

many hydrogen bonds

Answer 20

gives stability

individual hydrogen bonds are weak so allows strands to be separated for dna replication and protein synthesis’s

Question 21

how is the structure of DNA adapted for its function?

sequence of bases

Answer 21

codes for specific amino acid sequence in a polypeptide

Question 22

how is the structure of DNA adapted for its function?

complementary base pairing

Answer 22

enables information to be replicated accurately

Question 23

when does dna replication occur and what important role does it have

Answer 23

dna replication occurs in cell division

important role in the growth and reproduction of organisms

Question 24

outline the semi-conservative mechanism of DNA replication

Answer 24

1) when DNA replicates, the enzyme DNA helicase breaks the hydrogen bonds and separates the 2 polynucleotide strands

2) each of the strands acts as a template for the formation of 2 new complementary strands

3) individual DNA nucleotides align and attach by hydrogen bonding to the exposed bases on each template strand according to specific complementary base pairing

4) adenine pairs with thymine and cytosine pairs with guanine

5) the dna nucleotides in the new strand are joined together by phosphodiester bonds in condensation reactions catalysed by the enzyme DNA POLYMERASE

6) the 2 new dna molecules are identical to each other and the original DNA

Question 25

why is dna replication called semi conservative

Answer 25

because the 2 new dna molecules contain one of the original polynucleotide strands and a new one

Question 26

is RNA a relatively short or long polynucleotide molecule

Answer 26

short

Question 27

how does RNA differ in structure from DNA (3)

Answer 27

1) the pentose sugar is ribose not deoxyribose 2) the nitrogen base Thymine is replaced with Uracil 3) mRNA and tRNA are single stranded in comparison to double stranded dna

Question 28

what structure is messenger RNA (mRNA)

Answer 28

a linear structure and contains codons (mRNA base triplets)

Question 29

what is messenger rna (mRNA) involved in and where is it formed

Answer 29

mRNA is involved in protein synthesis it is formed in the nucleus during transcription

Question 30

how many different types of tRNA are there and where are they found

Answer 30

there are atleast 20 different types of tRNA molecules found in the cytoplasm

Question 31

what shape is tRNA molecules and why is it?

Answer 31

tRNA molecules have a ‘clover leaf’ structure due to the presence of hydrogen bonds between complementary base pairs

Question 32

what are the 2 things on a tRNA molecule ?

Answer 32

on one end of the molecule there is an ANTICODON ( 3 unattached tRNA nucleotide bases ) on the other end : a binding site for the attachment of a specific amino acid

Question 33

in prokaryotic cells what are dna molecules structure ?

Answer 33

they are short circular and are not associated with proteins called histones prokaryotes do not form chromosomes

Question 34

in eukaryotic cells what is the dna structure like how are chromosomes formed

Answer 34

dna is long and linear and are associated with proteins called histones together dna molecule and histones form a chromosome

Question 35

what is the dna like in mitochondria and chloroplasts of eukaryotic cells

Answer 35

it is like the dna of prokaryotes : short circular and not associated with proteins and does not contain introns

Question 36

what is a gene

Answer 36

a gene is a specific sequence of dna bases that code for the specific amino acid sequence of a polypeptide

Question 37

where are homologous chromosomes found

Answer 37

Homologous chromosomes are found in diploid organisms (organisms with two sets of chromosomes, such as humans). Each pair consists of one chromosome inherited from the mother and one from the father.

Question 38

what is the structure of homologous chromosomes

Answer 38

Each homologous chromosome is similar in length, shape, and centromere position. They contain the same genes arranged in the same loci. However, the alleles for each gene may differ. For example, one chromosome might have an allele for brown eyes, while its homolog might have an allele for blue eyes.