topic 3 the genome

Question 1

What is DNA?

Answer 1

A polymer made up of two strands forming a double helix, strands linked by a series of complementary base pairs joined together by weak hydrogen bonds

Question 2

what a the monomers of dna?

Answer 2

nucleotides

Question 3

what are DNA nucleotides made up of

Answer 3

• Common sugar
• Phosphate group
• One of four bases: A, T, C or G

Question 4

describe how nucleotides interact to form a molecule of DNA

Answer 4

● Sugar and phosphate molecules join to form a sugar-phosphate backbone in each DNA strand
● Base connected to each sugar
● Complementary base pairs (A pairs with T, C pairs with G) joined by weak hydrogen bonds

Question 5

State the full names of the four bases found in nucleotides

Answer 5

Adenine, Thymine, Cytosine, Guanine

Question 6

define genome

Answer 6

The entire genetic material of an organism

Question 7

What is a chromosome?

Answer 7

A long, coiled molecule of DNA that carries genetic information in the form of genes.

Question 8

define gene

Answer 8

segment of DNA that codes for a protein

Question 9

describe the method used to extract DNA from fruit

Answer 9

1. Place a piece of fruit in a beaker and crush it
2. Add detergent and salt, mix
3. Filter the mixture and collect the liquid in a test tube
4. Pour chilled ethanol into the test tube
5. DNA precipitates forming a fibrous white solid
6. Use a glass rod to collect the DNA sample

Question 10

Why is detergent added to the crushed fruit?

Answer 10

It disrupts the cell membranes, releasing DNA into solution

Question 11

why is salt added to the crushed fruit?

Answer 11

salt encourages the precipitation of DNA

Question 12

Why is chilled ethanol added rather water?

Answer 12

DNA is insoluble in ethanol, encouraging its precipitation