DNA

Question 1

Vector

Answer 1

A DNA molecule that is used as a vehicle to carry a particle DNA set,ent into a host cell as part of a cloning of recombinant DNA technique

Question 2

Transgenic bacterium

Answer 2

Genetically modified bacteria that carry the gene from other sources and are used for the production of a desired gene

Question 3

Plasmid

Answer 3

Circular DNA of bacteria molecule

Question 4

What are chromosomes

Answer 4

Long, thin like thread structures composed of DNA that is wrapped around a protein called histones.

Question 5

What is a gene

Answer 5

A short segment of DNA that codes for a particular protein - they carry the code for the synthesis of a particular protein and these proteins determine the characteristics of an organism

Question 6

Who we’re the scientists who formulated the double helix structure

Answer 6

James Watson and Francis Crick

Question 7

“Father of genetics” - by means of pea plant

Answer 7

Gregor Mendel

Question 8

Describe the structure of DNA

Answer 8

a giant molecule with 2 strands twisted in a double helix ladder - polymer made up of monomers (nucleotides)

Question 9

Nucleotides consist of 3 parts:

Answer 9

Sugar molecule (deoxyribose)
Phosphate group
Nitrogenous bases

Question 10

Name the 4 different types of nitrogenous bases

Answer 10

Adenine
Guanine
Cytosine
Thymine

Question 11

What are the purine bases

Answer 11

Adenine and guanine - larger molecules

Question 12

What are the pyrimidine bases

Answer 12

Cytosine and thymine - smaller molecule

Question 13

How are nitrogenous bases joined

Answer 13

By weak hydrogen bonds which are easily broken by enzyme action
Two hydrogen bonds between adenine and thymine
Three hydrogen bonds form between guanine and cytosine

Question 14

What importance is the sequence of a nucleotide

Answer 14

The sequence provides the code that gives instructions for the synthesis of proteins - this code is the genetic code or code of life. Note one DNA strand is always complimentary

Question 15

What is the role of DNA

Answer 15

• genetic code for protein synthesis
• regulates and controls expression of genes
• protects genes from mutations
• non coding DNA used in DNA fingerprinting

Question 16

What is non coding DNA

Answer 16

Only 2 % of DNA codes for proteins- the rest is non coding DNA and it regulates and controls the expression of genes in the coding DNA and protects genes from mutations

Question 17

DNA replication

Answer 17

Replication is the duplication of a DNA molecule to from to identical copies - this takes place during interphase of d the cell cycle

Question 18

What is the process of replication

Answer 18

1.DNA helix unwinds
2. DNA helicase unzips the molecule by breaking hydrogen bonds between base pairs
3.free bases are now available and exposed
4. DNA polymerase binds free nucleotides to complementary bases
5. Copying the template for each dna strand
6. Two exact complies are produced
7. DNA reshapes into a double helix
8. This them winds itself around a large protein called a histones forming a chromosome

Question 19

What is a codon

Answer 19

A sequence of 3 nucleotides which from a genetic code

Question 20

What is the importance of DNA replication

Answer 20

During mitotic division one mother cell divides to from 2 identical daughter cells
It’s essential that dna makes identical copies before cell division to ensure each daughter cell contains the same genetic information as the mother cell

Question 21

What is mtDNA

Answer 21

Occurs in mitochondria and is not related to chromosomal DNA that occurs in the nucleus
- it is the genes of mtDNA that code for ensures that control cellular respiration
- mtDNA is inherited via the maternal line + goes unchanged meaning it is possible to trace long lines of relatives