L3 DNA as genetic material

Question 1

What type of bond joins adjacent amino acids in a protein’s primary sequence?

Answer 1

Peptide bond

Question 2

What are the three Mendelian laws of inheritance?

Answer 2

• Segregation
• Independent assortment
• Dominance

Question 3

Who proposed the Sutton-Boveri theory of chromosomal inheritance?

Answer 3

Walter Sutton and Theodor Boveri

Question 4

What does the term ‘transforming principle’ refer to in genetics?

Answer 4

Hereditary material that changes the genotype of bacteria

Question 5

What is the purpose of the polysaccharide coat in S strain bacteria?

Answer 5

It protects some strains from the host immune system

Question 6

What experiment did Frederick Griffith conduct to study bacterial transformation?

Answer 6

He injected dead S bacteria with live R bacteria into mice

Question 7

What did Griffith conclude from his experiments?

Answer 7

Some hereditary material passed from S bacteria to R bacteria

Question 8

What did Oswald Avery and his colleagues determine was responsible for transformation?

Answer 8

DNA

Question 9

What component did Alfred Hershey and Martha Chase label to determine the genetic material of bacteriophages?

Answer 9

DNA and protein

Question 10

What is a bacteriophage?

Answer 10

A category of viruses that infect bacteria

Question 11

Which bacterium is the host for bacteriophage T2?

Answer 11

Escherichia coli

Question 12

True or False: The protein coat of a bacteriophage is injected into the bacterial host.

Answer 12

False

Question 13

Fill in the blank: The Sutton-Boveri theory provides a physical basis for Mendel’s _______.

Answer 13

Independent assortment

Question 14

What happens when S strain bacteria are heated and injected into mice?

Answer 14

No infection is established

Question 15

What are the steps in Avery’s transformation experiments?

Answer 15

• Systematically destroy each component
• Combine with live R bacteria
• Test for transformation

Question 16

What is the significance of the polysaccharide capsule in virulent bacteria?

Answer 16

It helps to evade the host immune response

Question 17

What did the experiments involving radioactive isotopes reveal about DNA?

Answer 17

DNA is the genetic material injected into bacteria

Question 18

What was the main question Griffith sought to answer through his experiments?

Answer 18

Can he transform the rough bacteria into smooth ones?

Question 19

Which type of bond is primarily responsible for holding together the primary structure of proteins?

Answer 19

Peptide bond

Question 20

What is the role of chromosomes in heredity according to the Sutton-Boveri theory?

Answer 20

They carry Mendel’s factors (genes)

Question 21

What was the outcome when live R bacteria were injected with dead S bacteria?

Answer 21

Infection was established

Question 22

What was a common misconception about DNA in the early 20th century?

Answer 22

Many thought DNA was too simple to be the genetic material

Question 23

What does the term ‘virulent’ refer to in the context of bacteria?

Answer 23

Bacteria that can cause disease

Question 24

Boveri and Sutton observed worms and grasshoppers. Why?

Answer 24

They observed chromosomes in these species because their chromosomes are large and few in number, amd therefore easy to see

Question 25

Which Streptococcus strain causes infection and illness?

Answer 25

S- strain

Smooth bacteria has polysaccharide coats that forms a capsule that protects itself from the host immune system

Question 26

Is an infection established when dead S bacteria is injected into mice together with live R bacteria?

Answer 26

Yes, the mouse is now infected

The bacteria now has a polysaccharide capsule

Question 27

Outline Hershey’s and Chase’s experiment

Answer 27

1. Label bacteriophage DNA or protein with radioactive isotope
2. Infect unlabelled bacteria with radioactive phage
3. Seperate phage ghosts from infected bacteria
4. Test bacteria and phage ghosts for radioactivity

Question 28

How did Hershey and Chase get rid of the phage ghosts?

Answer 28

They used a blender to make the phage ghosts fall off the bacteria

Bacteria themselves remain intact

Question 29

Is supernatent at the bottom of a centrifuged test tube or a pellet?

Answer 29

The pellet is at the bottom

Question 30

What did Hershey and Chase discover in their experiment?

Answer 30

Discovered that radioactivity was present in bacteria , therefore, it is the DNA that is being injected and directing the formation of new phage