Exam 4 : Classical Genetics I

Question 1

What is a genome?

Answer 1

All of the genetic hereditary material in an organism

Question 2

What is a genome made of?

Answer 2

All cells have genomes made from DNA molecules (chromosomes). Viruses can have DNA or RNA genomes

Question 3

Describe the bacterial genome

Answer 3

single circular DNA chromosome (DNA molecule)

Question 4

How do bacteria reproduce?

Answer 4

Binary fission

Question 5

What is binary fission?

Answer 5

One cell divides into two cells of equal size.

Question 6

Distinguish between a chromosome and chromatin.

Answer 6

A chromosome is a DNA molecule, a chromatin is the relaxed from of that DNA molecule

Question 7

Where are chromosome located in eukaryotic cells?

Answer 7

in the nucleus

Question 8

What is the chromosome made of?

Answer 8

DNA

Question 9

What is a centromere?

Answer 9

a protein complex attached to a chromosome, often seen as a pinch point. it is a complex that can bind two chromosomes together.

Question 10

What is the centromere’s role?

Answer 10

can hold sister chromatids together.

Question 11

what are sister chromatids and how do they arise?

Answer 11

when chromosomes are replicated (in S phase) they form a second DNA molecule that is identical to itself. It’s still a single chromosome, but made up of two sister chromatids.

Question 12

Distinguish between somatic cells and germ(gamete) cells.

Answer 12

somatic cells are cells of the body and are diploid (two copies of each chromosome). The gametes are sperm and egg, these are haploid cells with only one copy of each chromosome

Question 13

Describe the cell cycle. What are the different phases?

Answer 13

The cell cycle consists of two main phases: Interphase and M phase. Interphase consists of G1, S, G2 phases. M phase consists of mitosis/meiosis and cytokinesis. The cell cycle is the life cycle of a cell.

Question 14

What occurs during S phase?

Answer 14

S phases involves synthesis, chromosomes are duplicated. Centrosomes are also duplicated.

Question 15

What is interphase?

Answer 15

interphase is every part of the cell cycle except for M phase (mitosis/meiosis,cytokinesis). it consists of 2 gap phases and synthesis phase

Question 16

How is the cell cycle controlled?

Answer 16

Intracellular signals. Build up of a certain protein signal cell to move to another phases.

Question 17

Describe mitosis.

Answer 17

a type of cellular reproduction where ploidy number stays the same . one diploid cell becomes two diploid cells

Question 18

What are the phases of mitosis?

Answer 18

prophase, metaphase, anaphase, telophase, cytokinesis

Question 19

What occurs in prophase?

Answer 19

nuclear envelope disintegrates, chromatin is packages into condensed chromosomes, centrosomes move to opposite poles of the cell, mitotic spindle go between them

Question 20

What occurs in metaphase?

Answer 20

condensed chromosomes attach to spindle fibers by kinetochore complexes and line up on the imaginary metaphase plate, with a sister chromatid on opposite sides.

Question 21

What occurs in anaphase?

Answer 21

sister chromatids are pulled apart to opposite poles of the cell

Question 22

What occurs in telophase?

Answer 22

nuclei reform, spindle disappears, and condensed chromosomes relax back to chromatin

Question 23

Cytokinesis

Answer 23

cytokinesis is cell division

Question 24

How does cell division differ in plant vs. animal cells?

Answer 24

animal cells use actin fibers to cut cell in half. plant cells make a cell wall in the middle of the parent cell.

Question 25

What is a kinetochore?

Answer 25

A protein complex that is built onto the centromere. it attaches chromosomes to spindle fibers

Question 26

What is the role of microtubules in mitosis?

Answer 26

The mitotic spindle fibers made up of microtubules that pull chromosomes apart

Question 27

What is centriole?

Answer 27

A centriole is a microtubule organizing center and is made up of microtubules

Question 28

What is a centrosome?

Answer 28

The centrosome contains a pair of centrioles and organizes the mitotic spindle at each pole of the cell

Question 29

What is the metaphase plate?

Answer 29

An imaginary line through the center of the cell where chromosomes line up on the mitotic spindle.

Question 30

What is the mitotic spindle?

Answer 30

made of microtubules, attaches to chromatids and pulls them to opposite poles of the cell

Question 31

Diploid cell

Answer 31

two copies of every chromosome

Question 32

Haploid cell

Answer 32

one copy of every chromosome