Biological diversity part three

Question 1

What does DNA stand for?

Answer 1

Deoxyribo
Nucleic
Acid

Question 2

What chemicals make up the rungs of DNA? which chemicals go together?

Answer 2

Guanine (G)
Cytosine (C)
Adenine (A)
Thymine (T)
C and G always go together, A and T always go together.

Question 3

Where is DNA inside a cells?

Answer 3

Inside chromosomes inside the nucleus.

Question 4

How many chromosomes does each cell have?

Answer 4

Normal cells have 46 (23 pairs)

Gametes have 23

Question 5

What are sex chromosomes?

Answer 5

The 23rd pair of chromosomes that determine the sex and sexual characteristics of the individual. (In humans xx is female and xy is male)

Question 6

What is a gene?

Answer 6

An uninterrupted segment of DNA located on chromosomes.

Question 7

What are alleles?

Answer 7

Different forms of a gene.

Question 8

What is mitosis?

Answer 8

Cells duplicate. Occurs during growth and tissue repair.

Question 9

What are the steps of Mitosis?

Answer 9

1- Prophase: nucleus still there and chromosomes are condensing.
2- Metaphase: Chromosomes line up in the middle, nucleus is disassembled.
3- Anaphase: Sister chromatids separate to each side of the cell.
4- Telophase: Chromosomes are on each side, new nuclei form, cytokinesis occurs.

Question 10

What is Miosis?

Answer 10

Occurs to produce gametes. Divides twice.

Question 11

What are the steps of Miosis?

Answer 11

1- Prophase 1: chromosomes condense, line up with homologous pairs, crossing over occurs.
2- Metaphase 1: Homologous pairs line up in the middle.
3- Anaphase 1: Pairs split up into individual chromosomes on each side.
4- Telophase 1: Two new nuclei form and make two new cells.
5- Prophase 2: Spindles form but no homologous pairs or crossing over.
6- Metaphase 2: Chromosomes line up single file in middle.
7- Anaphase 2: chromatids separate and move.
8- Telophase 2: Two new nuclei form, cell division, four cells are the result.

Question 12

What is interphase?

Answer 12

The process that prepares a cell for mitosis or miosis. The DNA duplicates.

Question 13

What are homologous pairs?

Answer 13

Chromosomes are the same size and have the same types of genes in the same location.

Question 14

What is crossing over?

Answer 14

Homologous pairs transfer genetic information and exchange it between each other.

Question 15

What is a diploid?

Answer 15

Zygote.

Question 16

What is a Haploid?

Answer 16

A gamete.

Question 17

Who established the concept of dominant and recessive traits?

Answer 17

Gregor Mendel.

Question 18

What is true-breeding?

Answer 18

Reproduction with purebred parents (parents with ancestors with only the desired traits).

Question 19

How are dominant and recessive traits shown?

Answer 19

Dominant trait- uppercase letter

Recessive trait- lowercase letter of the same letter

Question 20

What is a punnet square?

Answer 20

A diagram used to predict the outcome of a particular cross or breeding experiment.

Question 21

What is incomplete dominance?

Answer 21

Alleles are neither dominant and both are shown as an intermediate format (combination of two traits).

Question 22

What is Co-Dominance?

Answer 22

Both alleles are dominant so both traits are shown.

Question 23

How can offspring unlike either parent be created?

Answer 23

More than one gene location or set of alleles can be responsible for some traits and complex mixing may create variation.