Biology Study Guide Ch. 5 Class Notes

Question 0

Porto-oncogene

Answer 0

Encodes proteins that promote the cell cycle and prevent a pop tonsils.

Question 1

Cell cycle

Answer 1

Orderly set of stages that takes place between the time a cell divides.

Question 2

Tumor suppressor genes

Answer 2

Encode proteins that stop the cell cycle and promotes a pop toss.

Question 3

Benign

Answer 3

A

Question 4

Malignant

Answer 4

A

Question 5

Mitosis

Answer 5

Is nuclear division that produces tho-daughter nuclei, each with the same number and kinds of chromosomes as the parental nucleus.

Question 6

Meiosis

Answer 6

Reducing chromosome number - occurs in any lifecycle that involves sexual reproduction and reduces the chromosome number such a way the daughter nuclei receives only one of each kind of chromosome.

Question 7

Meiosis I

Answer 7

The homologous chromosomes come together as a pair at the metaphor plate.

Question 8

Meiosis II - and fertilization

Answer 8

The sister chromatids separate the sister chromatids separate the daughter cells mature into gametes or sex cells sperm and egg – fuse together during fertilization.

Question 9

Fertilization

Answer 9

Restores the diploid number of chromosomes.

Question 10

Cell cycle

Answer 10

An orderly set of stages that takes place between the time the cell divides and the time the resulting cells divide.

Question 11

Interphase - Most of the time 90% v. 20h

Answer 11

• grows larger
• Organelles double (g1)
• DNA doubles (s)
• 3 stages

Question 12

G1

Answer 12

Accumulates materials needed for “s”

Question 13

G o

Answer 13

Cell cycle arrested

- cell continues to perform its normal functions.

Question 14

S

Answer 14

DNA replication

Question 15

One chromosome

Answer 15

Chromatid

Question 16

–>

Answer 16

2 sister chromatids

Question 17

G2

Answer 17

Cell synthesizes proteins need for division

- micro tules for spindle

Question 18

Mitosis

Answer 18

Division of the nucleus and genetic material.

Question 19

Cytokinesis

Answer 19

Division of the cytoplasm

Question 20

1a. Spindle

Answer 20

Ensures orderly distribution of chromosomes to the daughter cell nuclei

Question 21

Prophase

Answer 21

• division about to occur
• centro some begin moving –> opposite ends of nucleus
• spindle starts to appear
• nuclear envelop begins to fragment
• nucleoli begins to disappear

Question 22

Metaphase

Answer 22

Spindle has poles, aster, fibers

• metaphase plate
• chromosomes line up

Question 23

Anaphase

Answer 23

Centromeres divide (sisters)
- sisters -->daughter move -->opposite poles

Question 24

Telophase

Answer 24

- spindle disappears - nuclear envelope complex reassembles around the daughter chromosomes - nucleolus appears - cytokinesis underway

Question 25

Plants

Answer 25

No centrioles or aster - menstem tissue - shoot tip - root tip - tree girth

Question 26

Cytokinesis Plants

Answer 26

- cytoplasmic cleavage - new cell walls built - division of cytoplasm - between daughter cells - rigid cell wall prevents furrow

Question 27

Meiosis

Answer 27

- reducing chromosome number | - daughter cell receives only one of each kind

Question 28

Genetic variation

Answer 28

- crossing over - exchange of genetic material between non-sister chromatids - independent assortment - homologous pairs separate during Anaphase 1 - -> cells with different combinations of material and paternal chromosome.

Question 29

Fertilization

Answer 29

- restores diploid number of chromosomes | - -> new individual

Question 30

Meiosis

Answer 30

Occurs in the life cycle of sexually reproducing organisms.

Question 31

Meiosis in Detail

Answer 31

Meiosis

Question 32

First Division | Meiosis 1 is divided into

Answer 32

- Prophase 1 - Anaphase 1 - Metaphase 1 - Telophase 1

Question 33

Meiosis helps ensure

Answer 33

Genetic variation

Question 34

Genetic variation occurs in two ways

Answer 34

- crossing over | - independent assortment

Question 35

Meiosis 1

Answer 35

- When homologous pairs separate, each daughter cell receives one member of the pair. - The cells are now haploid.

Question 36

Meiosis II and Fertilization

Answer 36

* No replication of DNA occurs between Meiosis I And Meiosis II. * Centromes divide and sister chromatids migrate to opposite poles to become individual chromosomes. * Each of the four daughter cells produced has the haploid chromosome number. * Each chromosome is composed of one chromatid.

Question 37

Meiosis II and Fertilization

Answer 37

* Fertilization - Daughter cells of meiosis mature into gametes. * Sperm and eggs fuse in fertilization. - Fertilization restores the diploid number. * (n) + (n) = (2n) * Creates a cell that will develop into a new individual

Question 38

Second Division | * Phases of Meiosis II

Answer 38

- Anaphase II * sister chromatids separate and become daughter chromosomes that migrate toward the poles. - Telophase II * The spindle disappears * The nuclear envelope re-forms * Cytokinesis occurs.

Question 39

The importance of Meiosis

Answer 39

* Meiosis produces haploid cells from diploid cells. * Genetic variation produces cells no longer identical to parental cell. * Genetic variation occurs in two was. - First, crossing between nonsister chromatids. - Second, the independent assortment of chromosomes during Anaphase I.

Question 40

Prophase I

Answer 40

- Synapsids occurs, nuclear membrane breaks down. - Spindle appears, nuclear envelope fragments, and nucleoside disappears. - Homologues line up side by side and crossing over occurs. - After crossing over, chromatids held together are no longer identical - One has the original genetic material - One has recombined genetic material

Question 41

Metaphase I and Anaphase I

Answer 41

- Metaphase I | - Homologous pairs line up at metaphase plate such that maternal or paternal member may be oriented toward either pole.

Question 42

The importance of Meiosis

Answer 42

* Upon fertilization, bombing get of chromosomes from genetically different gametes help ensure offspring are not identical to parents. * This genetic variability is the main advantage of sexual reproduction. * Long-term, genetic variation increases the survival of a species.

Question 43

Occurrence | Meiosis occurs only at certain times of the life cycle of sexually reproducing organisms.

Answer 43

- After the reproductive organs mature to produce gametes. | - Mitosis takes place almost continuously in all tissues as part of growth and repair.

Question 44

5.6 The Human Life Cycle

Answer 44

- Both mitosis and meiosis are required. - At fertilization, a haploid (n) sperm and a haploid (n) egg fuse. - The resulting zygote has a diploid (2n) number of chromosomes. - The fetus divides by mitosis for growth and development. - After birth, mitosis allows continued growth and tissue repair.

Question 45

Spermatogenesis and Oogenesis in Humans

Answer 45

- Meiosis in the testes of males in called spermatogenesis. - Produces sperm - Meiosis in the ovaries of females is called Oogenesis. - Produces eggs.

Question 46

Spermatogenesis occurs in testes of human males.

Answer 46

- Process begins at puberty and continues throughout life. - Primary spermatocytes (2n) divide in meiosis 1 to form two secondary spermatocytes (1n). - Secondary spermatocytes divide in meiosis II to produce four spermatids. - Spermatids then mature to sperm (spermatozoa).

Question 47

Oogenesis - Begins in the fetus - Primary oocytes are arrested in prophase 1.

Answer 47

- Resumes at puberty - One primary oocyte continues the process of meiosis during each menstrual cycle. - Primary oocyte (2n) divides in meiosis 1 to produce one secondary oocyte (1n) and one polar body (1n) - Division is unequal as secondary oocyte receives most of the cell contents and half the chromosomes.

Question 48

Oogenesis (continued)

Answer 48

- If the secondary oocyte is fertilized, meiosis II will proceed. - Another unequal division will occur, with the egg receiving most of the cytoplasm. - A second polar body is also formed. - If the secondary oocyte is not fertilized, it disintegrates.