Science 5

Question 0

What do chromosomes contain?

Answer 0

Stretches of DNA called genes.

Question 1

Where are chromosomes located at?

Answer 1

In the nucleus of a cell.

Question 2

What does the coded information, that genes contain, control?

Answer 2

The heredity of particular traits.

Question 3

What is the code found in genes made up of?

Answer 3

The sequences of the nitrogenous bases of DNA

Question 4

What is each piece of the code in genes called?

Answer 4

Codon

Question 5

How many bases is each codon composed of?

Answer 5

Three

Question 6

How many codons are there?

Answer 6

64

Question 7

What does each codon match to?

Answer 7

A specific amino acid

Question 8

How many different amino acids are there?

Answer 8

20

Question 9

True or false. Codons never match to the same amino acid.

Answer 9

False

Question 10

What does a chain of amino acids form?

Answer 10

Protein

Question 11

What are the workhorses of the cell?

Answer 11

Proteins

Question 12

How many genes match to one protein?

Answer 12

One

Question 13

What is responsible for the expression of genetic traits?

Answer 13

Genes

Question 14

How do traits get spread from one generation to the next?

Answer 14

When organisms pass genes from one generation to the next

Question 15

What does each gene contains for influencing a trait of an organism?

Answer 15

Different information

Question 16

What is responsible for the inherited differences between one person and another?

Answer 16

The sum of all the proteins directed by the genes of an individual

Question 17

Chromosomes contain stretches of DNA called ________, which contains the information that controls particular traits for an individual.

Answer 17

Genes

Question 18

True or false? Genetic traits are expressed through the actions of proteins.

Answer 18

True

Question 19

Define a Genome.

Answer 19

A genome is a complete set of DNA for an individual that contains all genes.

Question 20

What are the two mechanisms in which mutations in the Genome can occur?

Answer 20

Errors during DNA replication or via a mutagen

Question 21

What is a mutagen?

Answer 21

A substance that induces mutations

Question 22

How do cells speed up the process of DNA synthesis?

Answer 22

By using an enzyme called DNA polymerase

Question 23

What can happen as DNA polymerase makes its way down a DNA strand?

Answer 23

Spontaneous errors may occur

Question 24

How can errors occur when DNA is being synthesized?

Answer 24

When DNA polymerase adds DNA bases along a strand

Question 25

In humans, how many errors can occur during each replication cycle?

Answer 25

One out of every 1000 genes

Question 26

What is the percentage of genes in the human Genome that can have errors?

Answer 26

Up to 5%

Question 27

What exists to reduce this error rate down to less than one DNA base in every 10 to the 9th to 10 to the 12th basis?

Answer 27

DNA repair mechanisms

Question 28

With the DNA repair mechanisms in play, how many genes in the human genome will have errors?

Answer 28

Less then .3%

Question 29

How is DNA repair mechanisms carried out?

Answer 29

DNA polymerase performs proofreading of the newly synthesized strands

Question 30

What happens if the DNA polymerase recognizes a missed pairing of bases?

Answer 30

It attempts to correct the problem by insertion of the proper base

Question 31

What other backup plan does the cell have to fix errors in DNA strands?

Answer 31

Mismatch repair

Question 32

After the new DNA has been replicated, what mechanism scans over the DNA to find any mismatches of bases?

Answer 32

Mismatch repair

Question 33

How does a DNA sequence get permanently altered?

Answer 33

If a mutation is able to pass through the cracks of mismatch repair and DNA polymerase proofreading

Question 34

How do certain types of cancer arise?

Answer 34

Because of failure in mismatch repair

Question 35

What substances can a cell be exposed to that is capable of damaging DNA?

Answer 35

Mutagens that can be anything from harmful chemicals to ultraviolet rays from the sun

Question 36

What mechanism inspects the DNA for the type of damage that is done by mutagens?

Answer 36

Excision repair

Question 37

Does modification by mutagens often occur over a section of DNA or over the individual bases?

Answer 37

A section of DNA

Question 38

How does excision repair work?

Answer 38

The excision repair mechanisms will cut the defective strand of DNA, remove those bases that are near, including the mutated ones, and allow DNA polymerase to generate a new, correct piece of DNA.

Question 39

What is a result of the excision repair mechanisms not functioning properly?

Answer 39

Certain skin diseases

Question 40

Define a germ cell.

Answer 40

Reproductive cells that give rise to sperm and ovum

Question 41

What is the only way that certain diseases, disorders or cancers can be passed on to future generations?

Answer 41

Only if they are present in the DNA of germ cells

Question 42

An individual may develop skin cancer due to excess sun exposure, but that individuals offspring will not have skin cancer unless those mutations are also found in ________.

Answer 42

Gametes

Question 43

Name the major enzyme responsible for DNA replication in cells.

Answer 43

DNA polymerase

Question 44

True or false. DNA in gametes is the DNA passed on to future generations.

Answer 44

True