(2) 1.4- DNA and Protein Synthesis

Question 1

What is conservative replication?

Answer 1

When the double helix remains intact and new strands form on the outside

Question 2

What is semi conservative replication

Answer 2

Where the double helix unzips and each strand replicates to produce a second new strand

Question 3

Describe the process of DNA replication- 1/3

Answer 3

When the DNA replicates, the two strands of the DNA molecule ‘unzip’ along the of hydrogen bonds and unravel. This is done by the enzyme DNA helicase the strands act as templates for the new DNA strands

Question 4

Describe the process of DNA replication 2/3

Answer 4

The exposed bases attract free DNA nucleotides and new hydrogen bonds are formed between matching base pairs

Question 5

Describe the process of DNA replication 3/3

Answer 5

DNA polymerase lines up and catalyses the linking up of the nucleotides along the template strand. DNA ligase catalyses the formation of phospodiester bonds between the two strands of DNA

(between the phosphate sugar and the deoxyribose sugar)

Question 6

Describe the structure of mRNA

Answer 6

Single strand
Contains a different sugar (Ribose)
Different base (uracil)
And does not form enormous and complex molecules like DNA

Question 7

What are the 3 main functions of mRNA

Answer 7

It carries the instructions for a polypeptide structure from the
DNA in the nucleus to the ribsomes where proteins are made

It picks up specific amino acids from the protoplasm and carries them to the surface of the ribsomses

Question 8

Where is mRNA formed

Answer 8

Nucleus

Question 9

what does mRNA do

Answer 9

Usually has instructions for one polypeptide

Question 10

What is the structure of mRNA

Answer 10

Single strand

Question 11

What sugar does mRNA contain

Answer 11

Ribose

Question 12

What is the coding strand of DNA knows as

Answer 12

sense strand

Question 13

What is the role of hydrogen bonds in protein synthesis 2/2

Answer 13

Hydrogen bonds maintain the helical structure of the RNA molecule

Question 14

What is the final stage of mRNA

Answer 14

the small mRNA molecules pass easily through the poles in the nuclear membrane carrying the instructions from the genes on the nucleus to the cytoplasm
They move to the surface of the ribsomes where the PS takes place

Question 15

What is the role of mRNA in PS 1/3

Answer 15

mRNA is the copy of the gentic material that is being syntehsised
It movies out the nucleus to the risbsomes

Question 16

What is the role of tRNA in PS 1/2

Answer 16

tRNA holds the amino acids in place

Question 17

Why can DNA replicate

Answer 17

-Double stranded

the two strands are held together by h+ bonds between A -T or G-C these bonds are easily broken

Question 18

How does DNA relate to its function

Answer 18

Stable structure- Due to the phsopahte backbone
Double stranded- replication can occur using one strand as template
weak h+ bonds- easy unzipping of the 2 strands in a double helix during replication

Question 19

How do phosphoidester bonds fromed

Answer 19

bonds form between the deoxyribose sugar and the phsopahte group in a condensation reaction and a molecule of water is removed