TOPIC 1-DNA and RNA

Question 1

What type of acids are DNA and RNA?

Answer 1

Nucleiuc

Question 2

Where are they found?

Answer 2

In all living cells

Question 3

What does DNA stand for?

Answer 3

Deoxyribonucleic acid

Question 4

What is the function of DNA?

Answer 4

To store genetic information

Question 5

What is the function of RNA?

Answer 5

To transfer genetic information from the DNA to the ribosomes

Question 6

How is the function of ribosomes linked to RNA?

Answer 6

They read RNA to make polypeptides (proteins) in the process of translation

Question 7

What are ribosomes made of?

Answer 7

RNA and proteins

Question 8

What is a nucleotide?

Answer 8

A biological molecule which is made of 3 components:
-A pentose sugar (a sugar with 5 carbon atoms)
-A nitrogen-containing organic base (an organic base contains carbon)
-A phosphate group

Question 9

What do many nucleotides join together to form?

Answer 9

Polynucleotide strands/chains

Question 10

How do the nucleotides join up to create a polynucleotide structure?

Answer 10

Through a condensation reaction between the phosphate group of one nucleotide and the sugar of another

Question 11

What bond is formed between the phosphate group and the sugar?

Answer 11

Phosphodiester

Question 12

What does a phosphodiester bond contain?

Answer 12

The phosphate group and 2 ester bonds

Question 13

What is the sugar-phosphate backbone?

Answer 13

The chain of phosphates and sugars

Question 14

What is the structure of DNA?

Answer 14

A double helix structure- the DNA molecule is formed from two separate strands (polynucleotides) which wind around each other to form a spiral

Question 15

How is the structure of DNA related to its function?

Answer 15

DNA molecules are really long and are coiled up very tightly so a lot of genetic information can fit into a small space in the cell nucleus

Question 16

Each DNA nucleotide has the same (1) ___ and (2)___

Answer 16

1. Sugar
2. Phosphate

Question 17

What varies in a DNA molecule?

Answer 17

The base

Question 18

What are the 4 possible bases?

Answer 18

-Adenine (A)
-Thymine (T)
-Cytosine (C)
-Guanine (G)

Question 19

What are the complementary base pairings?

Answer 19

-Adenine + Thymine (A+T)
-Guanine + Cytosine (G+C)

Question 20

How many hydrogen bonds form between A and T?

Answer 20

2

Question 21

How many hydrogen bonds form between G and C?

Answer 21

3

Question 22

Why can you only have complementary base pairings?

Answer 22

So there are equal amounts of A: T and G: C in the DNA molecule

Question 23

The two polynucleotide strands are…

Answer 23

Antiparallel

Question 24

How does the structure of RNA differ from the structure of DNA?

Answer 24

-The sugar in RNA nucleotides is a ribose sugar (not deoxyribose), although it is still a pentose sugar.
-Uracil (U, a pyrimidine) replaces thymine as a base, Uracil always pairs with Adenine in RNA
-The nucleotides form a single polynucleotide strand, not a double one
-RNA strands are much shorter than most DNA polynucleotides

Question 25

What caused some scientists to doubt that DNA carried the genetic code?

Answer 25

-First observed in the 1800s
-It has a relatively simple chemical composition
-Some argue that proteins must carry genetic information, which is much more chemically varied

Question 26

What did experiments show by 1953?

Answer 26

That DNA was the carrier of the genetic code, the double helix structure, which helps DNA to carry out its function

Question 27

Which scientists discovered the structure of DNA and their model of the DNA double helix?

Answer 27

Watson and Crick