DNA 2 Structure and replication

Question 1

2-4% and 96-98% and other facts

Answer 1

of our DNA codes for protein and the rest (96-96) is nonsense.
30,000 genes in a human.
All cells in our body (except sex cells)

Question 2

Define DNA

Answer 2

Deoxyribonucleic Acid.

Question 3

Define RNA

Answer 3

Ribonucleic Acid.

Question 4

What is a nucleotide?

Answer 4

A building block of DNA : Nitrogenous base + sugar+phosphate group
Sugar-phosphate forms backbone of DNA by joining with Nitrogenous base. (polynucleotide)

Question 5

What is the difference between DNA replication and protein synthesis

Answer 5

Replication is where DNA replaces cells, on a regular basis.

Question 6

What is protein synthesis

Answer 6

Protein synthesis has 2 distinct stages including transcription and translation to form proteins the body needs.

Question 7

Name the Purine nucleotides

Answer 7

Adenine and guanine these have double ringed nitrogenous bases

Question 8

Name the Pyrimidine nucleotides

Answer 8

Cytosine, Thymine and Uracil (urasil replaes thymine in RNA) These have single ringed bases. (easy to remember as they have y in them)

Question 9

What are purines and pyrimidines?

Answer 9

compounds that make up the 2 groups of nitrogenous bases that are part of DNA. The are self-limiting and self regulating and both are needed in the cell in equal amounts

Question 10

What distinguishes a polynucleotide?

Answer 10

The presence of a sugar-phosphate back-bone

Question 11

What type of bond is a nucleotide?

Answer 11

A Hydrogen bond (through dehydration) Guanine and Cytosine slightly stronger. With 3 ‘H’ the Thymine and Adanine have 2 ‘H’ .
These bonds join the strands of DNA together, in a double Helix.

Question 12

How are DNA strands read?

Answer 12

They are always read from 3’ (prime) - 5’ (prime)
strands are complimentary and alwasy reflect the A:T and the C:G bonds that are always together. Capital letter of nucleotide makes up the code.

Question 13

Human RNA

Answer 13

Contains Ribose sugar in nucleotide
Is normally single stranded
contains C,G,A,U
Considered to be molecular slave of DNA.
3 types mRNA, tRNA, rRNA
all 3 involved in protein synthesis

Question 14

Traits of DNA

Answer 14

major cellular site is nucleus
Major function: It is the genetic material  Directs protein synthesis and replicates itself before cell division
Sugar: Deoxyribose
Bases: A,G,C,T
Structure Double stranded helix

Question 15

Traits of RNA

Answer 15

Major cellular location: Cytoplasm
Major Function: Carrie out the genetic instruction for protein synthesis
Sugar: Ribose
Bases: A,G,C,U
Structuere is single strand, straight or folded.

Question 16

What is DNA replications

Answer 16

Before a cell divides it must replicate its DNA.

Identical copies of a cells genes can be passed to daughter cells.

Question 17

Describe the cell cycle

Answer 17

(interphase) 4 stages
GI stage: cell is preparing it has everything it needs
S Stage: protein synthesis occurs: if anything not right the cycle would be halted. Stops at each stage to check cell is right. Checks that the neucleotides are present in the cell that it needs.
G2 stage: cell will check if anything is wrong in the copiying process cell dies.
Mitosis : actual dividing of cell

Question 18

Describe the flow of genetic information

Answer 18

DNA replicates itself, or begins process of Protein synthesis:

Question 19

Replication of DNA:

Including the 3 enzymes and their functions

Answer 19

DNA Polymerase is the enzyme involved. An enzyme that forms a long chain of information
Helicase is the enzyme that unzips/splits DNAs double Helix.
Cellular machinery (primer and Polymerase) latch on to strand and pull all the nucleotide’s and place them in the right order to match the template.
Replication has a leading and lagging strand (leading strand always read from 5-3. Lagging strand reads in other direction but enzyme works in segments needing to go back to read it.
RNA primer sits on strand and initiates.
3 enzymes to remember are DNA polymerase, Heliase and Primer.