DNA, Genes And Chromosomes

Question 1

Nuclear eukaryotic DNA is ____________

Answer 1

Linear

Question 2

Describe the structure of DNA

Answer 2

• long, can be wound up by just ones
• double helix
• linear

Question 3

How and why does prokaryotic DNA condense?

Answer 3

It supercoils could to fit within the cell

Question 4

What does DNA contain?

Answer 4

Genes

Question 5

What is a gene?

Answer 5

A sequence of DNA bases that code for polypeptide or functional RNA

Question 6

What determines the order of amino acid within a polypeptide?

Answer 6

The order of bases

Question 7

What sections make up DNA?

Answer 7

• exons and introns

Question 8

What are exons?

Answer 8

Genes that do code for polypeptides

Question 9

What are introns?

Answer 9

Non-coding genes within a sequence

Question 10

What are alleles?

Answer 10

Genes that exist in more than one form

Question 11

What are the two types of RNA?

Answer 11

mRNA- carries genetic code from DNA to Ribosomes
tRNA- used in translation, carries specific amino acids to ribosomes, it has a clover shape

Question 12

What is the first stage of Protein Synthesis?

Answer 12

Transcription

Question 13

Describe the process of protein synthesis

Answer 13

1. RNA helicase attached to DNA helix at the beginning of a gene
2. Hydrogen bonds between the two strands are hydrolysed separating the strand and uncoiling it
3. One of the strands it’s then used as a template to make an mRNA copy
4. RNA polymerase joins together free nucleotides to the base via complimentary base pairing, AU, CG
5. RNA polymerase moves along the DNA separating the strands and assembling the pre-mRNA strand
6. Hydrogen bonds between the uncoiled DNA reform and coil the DNA strands back into a double helix
7. When RNA polymerase reaches a stop signal it detached from the DNA
8. pre-mRNA is spliced and then moves out of the nucleus through the pore

Question 14

What’s the second stage of Protein Synthesis?

Answer 14

Translation

Question 15

Describe the process of Translation

Answer 15

1. mRNA attaches to a ribosome and tRNA then carry the specific amino acids to it, ATP providing the energy needed
2. A tRNA molecule with an anticodon that’s that’s complimentary to the first codon on the mRNA attaches to the mRNA via specific base pairing
3. A second tRNA molecule attaches to the next codon on the mRNA the same way
4. The two amino acids attached to the tRNA molecules are joined via a peptide bond
5. A third tRNA molecule binds to the next codon on mRNA
6. This process continues, forming a polypeptide chain
7. The polypeptide chain moves away from the ribosome and translation is complete