Basics

Question 1

DNA:

Answer 1

where the hereditary material in almost all organisms is stored

Question 2

DNA consist of:

Answer 2

-The double helix (2 long strands that form a spiral)

-Nucleotides (individual units of each strand of DNA)

Question 3

A nucleotide is composed of:

Answer 3

a phosphate molecule, a sugar molecule, and a base molecule (ex. guanine)

Question 3

Hydrogen bonded pairs:

Answer 3

Adenine + Thymine (purines) & Guanine + Cytosine (pyrimidines)

Question 4

The DNA sequence in every cell of an organism is called:

Answer 4

The organism genome

Question 5

Genes are:

Answer 5

sections of DNA that contain genetic information for the inheritance of specific traits (ex. hair colour)

Question 6

Homologus Chromosomes

Answer 6

pair of chromosomes that appear similar in terms of length, centromere location, and banding pattern (one from mother one from father)
*not necessarily identical

Question 7

Alleles

Answer 7

different forms of the same gene (the different forms account for the difference in specific traits)
-ex. Blonde vs Brown hair

Question 8

Replicating DNA

Answer 8

double helix unwinds, each strand serves as a template for a new strand (each new DNA molecule conserves half of the original)

Question 9

How many chromosomes do humans have?

Answer 9

46, 23 pairs, half from mom half from dad

Question 10

What is another term used to describe a complete set of chromosome?

Answer 10

a complete set of chromosomes can also be called your genome

Question 11

How is DNA structured?

Answer 11

a double helix containing a phosphate group, a sugar group, and a base

Question 12

What is DNA short for?

Answer 12

deoxyribonucleic acid

Question 13

What letters make up DNA?

Answer 13

(A)denine, (C)ytosine, (G)uanine, (T)hymine

Question 14

Which part of a nucleotide varies?

Answer 14

the base (A,T,G,C)

Question 15

What does a series of nucleotides (called a gene) code for?

Answer 15

a series of nucleotides code for protein

Question 16

The cell theory states:

Answer 16

All living things are made up of cells, cells are the basic units of structure and function in living things, new cells are produced from existing cells

Question 16

State three examples of a protein produced by the body.

Answer 16

-Hair
-Fingernails
-Insulin

Question 17

In multicellular organisms there are 3 functions of cell division:

Answer 17

1. growth of organism
2. repair of tissues and organs that have been damaged
3. maintenance in repairing damaged or dead cells

Question 18

Gametes

Answer 18

reproductive cells (sperm and egg)

Question 19

Zygote

Answer 19

a diploid cell resulting from the fusion of two haploid gametes; a fertilized egg.

Question 20

Haploid (n)

Answer 20

An organism or cell having only one complete set of chromosomes.

Question 21

Diploid (2n)

Answer 21

An organism or cell that contains pairs of chromosomes.

Question 22

Are human gametes haploid or diploid?

Answer 22

haploid (n= 23 chromosomes)

Question 23

Genetic reduction

Answer 23

a form of cell division that produces daughter cells with half the number of chromosomes of the parent cell.

Question 24

Genetic recombination

Answer 24

products of meiosis have different combinations of alleles, which gives rise to offspring that are genetically different from one another and their parents which = genetic variation.

Question 25

What is an Autosome?

Answer 25

Any chromosome that is not a sex chromosome

Question 26

How many autosomes and sex chromosomes do humans have?

Answer 26

Autosomes: 22 pairs

Sex chromosomes: 1 pair

Question 27

What are sex chromosomes?

Answer 27

chromosomes that carry the genes that determine the sex of an organism

Question 28

What are the two ways that genetic variation can occur?

Answer 28

independent assortment & crossing over

Question 29

What is independent assortment?

Answer 29

the maternal origin is oriented toward one pole of the cell and the paternal origin is oriented toward the other pole of the cell

so, depending on how the chromosomes line up, a # of different combinations may be found in gametes.

Question 30

What is crossing over?

Answer 30

while homologous chromosomes are lined up in prophase 1, non-sister chromatids of homologous chromosomes may exchange pieces of chromosomes

• dramatically increases the genetic diversity of gametes produced

*only homologous chromosomes swap together

Question 31

What are the 2 chromosomal errors that can occur?

Answer 31

-Changes in chromosome structure

-Changes in chromosome number

Question 32

Errors that can occur to chromosome structures include:

Answer 32

-Deletion: a piece of a chromosome is deleted

-Duplication: a section of a chromosome appears 2 or more times in a row

-Inversion: a section of a chromosome is inverted

-Translocation: a segment of one chromosome becomes attached to a different chromosome

diagrams in notebook

Question 33

Changes in chromosome structure:

Answer 33

During crossover, the chemical bonds that hold DNA together in the chromosome are broken and reformed

Sometimes the chromosomes do not reform correctly

-non-homologous pairs may also crossover, producing chromosomes with genes not normally on that chromosome

Question 34

Changes in chromosome number:

Answer 34

-sometimes homologous chromosome pairs or sister chromatids do not separate as they should during meiosis, this is known as non-disjunction

-as a result, gametes produced have too few or too many chromosomes

*occurs in anaphase 1 & 2

-In anaphase 1: occurs when the homologous pairs do not separate to opposite poles; instead one entire pair is pulled toward the same pole

-in anaphase 2: occurs when sister chromatids do not separate to opposite poles; instead each chromatid is pulled toward the same pole

Question 35

Somatic cell

Answer 35

any cell of a living organism other than the reproductive (sperm and egg) cells.

Question 36

Oncogenes

Answer 36

a mutated gene that has the potential to cause cancer

-before an oncogene becomes mutated, it is called a proto-oncogene, and it plays a role in regulating normal cell division