Chapter 24-DNA: The Regulation of Life

Question 1

By the mid 1940s, scientists had begun to realize that a mysterious substance in the nucleus of a cell, known as __________________, somehow controlled heredity.

Answer 1

Deoxyribonucleic acid, DNA

Question 2

Who were the two biochemists who deduced the actual structure of DNA, which revealed that each gene of an organism is the part of the DNA molecule that controls a particular trait?

Answer 2

James D. Watson

Francis H. C. Crick

Question 3

The discoveries by biochemists James D. Watson and Francis H. C. Crick revealed that each _____________ of an organism is the part of the DNA molecule that controls a particular trait.

Answer 3

Gene

Question 4

Within your body, every somatic cell contains 46 _________________ in the nucleus, each of which contains one molecule of DNA.

Answer 4

Chromosomes

Question 5

Ordinarily, short segments of each DNA molecule are coiled on protein “spools” called:

Answer 5

Histones

Question 6

Groups of eight histones (protein spools) are clustered together to form a:

Answer 6

Nucleosome

Question 7

The millions of protein “spools” filling the nucleus give the nucleus a grainy texture when viewed under a powerful microscope. Scientists after refer to DNA stored in this manner as:

Answer 7

Chromatin

Question 8

The bundles of tightly coiled _________ are the chromosomes that are visible during mitosis and meiosis.

Answer 8

DNA

Question 9

Besides DNA, the other important nucleic acid in the cell is:

Answer 9

Ribonucleic acid, RNA

Question 10

Both nucleic acids, DNA and RNA, are composed of special molecules called:

Answer 10

Nucleotides

Question 11

Each DNA molecule consists of two long nucleotide chains that are twisted about one another, giving the molecule the shape of a twisted ladder. Scientists refer to this double-spiral structure as a:

Answer 11

Double helix

Question 12

What are the four different types of bases that make up the “rungs” in a DNA molecule?

Answer 12

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

Question 13

Only one type of __________________ will “fit” another. (thymine+adenine), (guanine+cytosine).

Answer 13

Base (guanine, cytosine, adenine, thymine)

Question 14

The process in which only one type of base will “fit” another is called:

Answer 14

Base pairing

Question 15

The structure of an RMA molecule is similar to that of DNA, except the ___________ consists of only one strand instead of two.

Answer 15

RNA

Question 16

Three of the bases in DNA (guanine, cytosine, and adenine) are identical to those of DNA. However, RNA uses a base called __________________ instead of thymine.

Answer 16

Uracil

Question 17

What is the process by which DNA makes a copy of itself before cell division called?

Answer 17

Replication

Question 18

Through what process does the cell copy the information contained in the DNA into messenger RNA (mRNA) molecules?

Answer 18

Transcription

Question 19

Through what process do mRNA molecules provide the information to the ribosomes to make protein molecules through:

Answer 19

Translation

Question 20

Scientists have found that many viruses, like the HIV virus, are able to make DNA starting from molecules of RNA in a process called:

Answer 20

Reverse transcription

Question 21

When a new protein is needed, the DNA coding for that protein is transcribed into a __________________ molecule?

Answer 21

Messenger RNA

Question 22

Molecules of _______________ collect free amino acid molecules and carry them to ribosomes to be assembled into proteins.

Answer 22

Transfer RNA

Question 23

What serves as the part of the structure of the ribosomes themselves and is the most abundant type of RNA in the cell?

Answer 23

Ribosomal RNA

Question 24

What is a consecutive sequence of three nucleotides in the mRNA which translates into one specific amino acid?

Answer 24

Codon

Question 25

The equivalence of the codons to amino acids is given by the _________________, a table with all the possible combinations of nucleotides and the amino acids they generate.

Answer 25

Genetic code

Question 26

What instruct the ribosome to stop translation?

Answer 26

Stop codons

Question 27

What, also called an AUG, indicates the beginning of a protein and also codes for the amino acid methionine?

Answer 27

Start codon

Question 28

What is the process of synthesizing proteins from the RNA pattern called, and is called thus because the cell has in a sense “translated” the DNA code into a functional protein?

Answer 28

Translation

Question 29

Many people have become concerned about the ramifications of _______________, which can be used to produce a genetic twin of any organism.

Answer 29

Cloning

Question 30

What are intervening DNA sequences with no apparent function?

Answer 30

Introns

Question 31

What are the small, random changes in the DNA called that can be thought of as “typographical errors” in the genetic material?

Answer 31

Mutations