Chapter 4 - Genetics and Cellular Function

Question 0

What do the nucleotides in DNA consist of?

Answer 0

A sugar, phosphate group, and nitrogenous base

Question 1

What is DNA?

Answer 1

A polymer of nucleotides

Question 2

What are the nitrogenous bases?

Answer 2

Cytosine (C), thymine (T), adenine (A), and guanine (G)

Question 3

What is DNA described as?

Answer 3

A double helix that resembles a spiral staircase

Question 4

What is each side piece composed of?

Answer 4

Phosphate groups alternating with deoxyribose (sugar)

Question 5

What is the essential function of DNA?

Answer 5

To carry instructions for the synthesis of proteins

Question 6

What does RNA consist of?

Answer 6

Only one nucleotide chain

Question 7

What are the types of RNA?

Answer 7

a) mRNA- the molecule that carries the genetic code from the nucleus to the cytoplasm.
b) tRNA- binds a free amino acid and delivers it to the ribosome.
c) ribosome- the molecule that “reads” the mRNA.

Question 8

What is a gene?

Answer 8

An information-containing segment of DNA that codes for the production of a molecule of RNA

Question 9

What is a genome?

Answer 9

All the DNA in a set of 23 pairs of chromosomes

Question 10

What happens in protein synthesis?

Answer 10

1. Transcription
2. Translation
3. Termination

Question 11

What is Transcription?

Answer 11

The process of copying genetic instruction from DNA to a complementary RNA

Question 12

What is Translation?

Answer 12

The process of reading the mRNA an synthesizing the protein encoded in the nucleotide sequence

Question 13

What happens during Initiation?

Answer 13

i) mRNA outside the nucleus forms a loop.
ii) The ribosomal subunits and the initiator tRNA bind to the mRNA.
iii) The ribosome begins sliding along the mRNA reading bases.

Question 14

What happens during Elongation?

Answer 14

i) The tRNA that matches the next sequence on the mRNA binds to the ribosome.
ii) The amino acid from the previous tRNA binds to the new amino acid on the new tRNA.
iii) The ribosome slides over the mRNA and the previous tRNA leaves the ribosome.

Question 15

What is Termination?

Answer 15

The ribosome reaches the stop sequence on the mRNA and releases from the mRNA

Question 16

What happens in DNA Replication?

Answer 16

1. The double helix unwinds.
2. The enzyme DNA polymerase moves along the strand, reads the exposed base and arranges a match with complementary free nucleotides.
3. Each old (parental) strand has a new (daughter) complementary strand resulting in two identical copies of daughter DNA.

Question 17

What are the functions of Mitosis?

Answer 17

a) Development of an individual.
b) Growth of tissues and organs after birth.
c) Replacement of cells.
d) Repair of damaged tissue.

Question 18

What are the phases of Mitosis?

Answer 18

a) Prophase
b) Metaphase
c) Anaphase
d) Telophase

Question 19

What happens during Prophase?

Answer 19

i) Chromosomes coil into compact rods which consist of two identical sister chromatids.
ii) The nuclear envelope disintegrates.

Question 20

What happens during Metaphase?

Answer 20

The chromosomes align at the cell equator

Question 21

What happens during Anaphase?

Answer 21

Sister chromatids are pulled apart to opposite poles of the cell

Question 22

What happens during Telophase?

Answer 22

i) A new nuclear envelope forms around the chromatids.

ii) The chromatids uncoil.

Question 23

What is Cytokinesis?

Answer 23

Division of the cytoplasm into two cells