Mod A Unit 2, Les 6 DNA Structure And Function

Question 1

What is DNA?

Answer 1

The genetic material of a cell that contains information needed for the cell’s growth and other activities. It also determines the inherited characteristics of an organism

Question 2

Which material does most of the work of a cell and also makes up most of the cell’s structure?

Answer 2

Protein

Question 3

What is meant by the DNA’s code?

Answer 3

This is a set of rules and symbols used to carry information

Question 4

The structure of DNA is described as a twisted ladder shape. What is the term used to describe this?

Answer 4

Double helix

Question 5

1. The two sides fo the DNA ladder often called the “backbone” is made by alternating two materials called…? (See p. 150 for more details)
2. The rungs in the ladder are made by materials called ….?

Answer 5

1. Sugars and phosphates

2. Pairs of bases

Question 6

A base, a sugar, and a phosphate group make a building block of DNA known as a ….? these repeating chemical units join together to form the DNA molecule.

Answer 6

A nucleotide

Question 7

These 4 bases are called: (remember “All Tigers Can Growl”)

Answer 7

Adenine, Thymine

Cytosine, Guanine

Question 8

The bases pair together in a special, complimentary way. (They fit together just right) Which two pairs always go together?

Answer 8

Adenine with Thymine

Cytosine with Guinine

Question 9

What are the segments of DNA that each relate to a certain trait?

Answer 9

Genes

Question 10

The process by which a cell is able to make copies of DNA molecules is called…?

Answer 10

Replication

Question 11

What happens during replication? Remember, this happens before a cell divides.

Answer 11

1. The 2 strands of DNA separate (like being unwound)
2. The bases on each side of the molecule are used as a pattern for a new strand to be made. 3. Adenine attach to thymine etc.new strands are made with 1 old DNA strand and 1 new one. (See p. 152 for a diagram)

Question 12

What are mutations?

Answer 12

Changes in the number, type, or order of bases on a piece of DNA

Question 13

What are the 3 types of mutations? Explain each

Answer 13

1. Deletion: a base is left out
2. Insertion: a extra base is added
3. Substitution: one base replaces another (most common type) Note: mutations can be beneficial, neutral, or harmful)

Question 14

How do mutations happen?

Answer 14

Usually, there are random errors. Another possibility is when DNA is damaged by chemical agents called mutagens (examples are ultraviolet light or chemicals in cigarettes.

Question 15

What is a genetic disorder?

Answer 15

This is a disorder that results fro mutations that harm the normal function of a cell. (Such as sickle cell anemia). They are inherited (passed down from parents)

Question 16

How does the cell use DNA to make proteins?

Answer 16

1. Some Info from DNA is copied to ribonucleic acid (RNA).
2. The copy is used to build proteins. Not all instructions are needed all the time. Some DNA is protected inside the cell’s nucleus

Question 17

RNA contains a sugar-phosphate backbone and 4 bases. What are these bases called?

Answer 17

Adenine (A), guanine (G), cytosine (C),and uracil (U). (First 3 are just like the bases in DNA)

Question 18

There are 3 types of RNA. Each type has a special role in making proteins. What are they called?

Answer 18

1. Messenger RNA,
2. Ribosomal RNA
3. Transfer RNA

Question 19

What is transcription?

Answer 19

This is when a cell needs a set of instructions for making a protein and it makes an RNA copy of the needed section of DNA. DNA and messenger RNA are needed (mRNA).

Question 20

Explain the process of transcription.

To help you remember, imagine taking a book off of the bookshelf and only copying the pages you need to do your work!

Answer 20

*only specific genes needed are copied from the DNA. 1. DNA is used as a template to make a complementary strand of mRNA. 2. DNA opens up where the gene is located. 3. RNA bases match up to the bases on the DNA template. When done, the mRNA is released and the DNA molecule closes.

Question 21

What is translation?

Answer 21

The process of making proteins from RNA

Question 22

What is a ribosome?

Answer 22

An organelle made of ribosomal RNA (rRNA)

Question 23

What happens during translation?

Answer 23

1. The mRNA passes through the ribosome.
2. Transfer RNA (tRNA) molecules deliver amino acids to the ribosome
3. Each group of 3 passes on mRNA codes for 1 amino acid and they join together to make a protein. (See p. 155)

Question 24

What is Erwin Chargaff known for?

Answer 24

He found that:
Amount of Adenine = amount of thymine
Amount of guanine = amount of cytosine

Question 25

What are Rosalind Franklin and Maurice Wilkins known for?

Answer 25

Took x-ray images of DNA molecule

Question 26

What are James Watson and Francis Crick known for?

Answer 26

Proposed a double-helix model of DNA