PP 9 Meiosis & Mitosis

Question 0

• • How many divisions does it take to complete mitosis, meiosis?
• • Do homologous chromosomes crossover in mitosis, meiosis if so what phase?
• • When do centromeres divide in meiosis,mitosis?
• • what does meiosis generates? Mitosis?
• • Which process results in copying and growth? Which is necessary for sexual reproduction?
• • Do the daughter cells in mitosis have diff. Genetic info as parent, meiosis?
• • Do daughter cells have the same # of chromosomes as parent cells?

Answer 0

• • 1- mitosis/ 2- meiosis
• -do not cross over in mitosis/ Do in meiosis. Prophase 1
• • Mi/ centromeres divide in anaphase. Me/ centromeres divide in anaphase 2
• • Mi/ generates body cells Me/ generates sex cells
• • Mi/ copying & growth Me/ necessary for sexual reproduction
• • Mi/ daughter cells have same genetic info. Me/ daughter cells are genetically diff. From parent

– Me/ daughter cells have half the # chromosomes as parent cell (haploid)
Mi/ daughter cells have same # of chromosomes as parent cell ( diploid)

Question 1

What is cell division?

Answer 1

Grow & replace 2 fundamental qualities of life

Question 2

Mitosis & binary fission are means of sexual or asexual reproduction?

Answer 2

Asexual (w/out sex)

Question 3

The cell cycle consists of 3 parts, name them?

Answer 3

• • interphase (G1, S, G2)
• • Mitosis (Prophase, Metaphase, Anaphase, Telophase,)
• • Cytokinesis ( cell splits & divides cytoplasm)

Question 4

What does Mitosis do in multi-cellular organisms?

Answer 4

• • causes growth by increasing # of cells
• • replaces lost cells
• • repairs injuries

Question 5

Briefly explain what happens in each phase of Mitosis?

Answer 5

• Interphase/ cells growth, chromosomes double, cells grow some more
• Prophase/ chromosomes condense, nuclear membrane disappears, centrioles go to opposite ends of cell, spindle fiber forms
• Metaphase/ chromosomes move to middle, spindle fibers connect to centromere
• Anaphase/ centromeres pull apart, sister chromatids become separate, strait to move to opposite ends of poles of cell
• Telophase/ chromosomes uncoil, nuclear membrane forms, spindle fiber disappears
• Cytokinesis/ cell splits & cytoplasm divides

Question 6

Cells spend 90% of their time in interphase. What happens in the 3 phases?

Answer 6

• • G1/ cells grow
• • S (synthesis)/ chromosomes double & divide to make identical pairs
• • G2/ cells grow more & produce needed proteins necessary for cell division

Question 7

2 classes of proteins code for checkpoint proteins, Name them, tell what they are used for?

Answer 7

• Proto-oncogen(yes) code for proteins that encourages cell division
• tumor suppressor gene (no) discourage cell division

Question 8

Name phase. Of Mitosis, Meiosis 1, & Meiosis 2.

Answer 8

Mi (interphase,prophase,metaphase,anaphase,telophase,cytokinesis)

Me 1 (interphase 1, prophase 1, metaphase 1, anaphase 1, telophase 1, cytokinesis 1)

Me 2 ( prophase2, metaphase2, anaphase2, telophase2, cytokinesis2)

Question 9

Mutagens are agents that damage what?, Give an example of a mutagen.

Answer 9

– DNA

- carcinogens cause mutations that lead to cancer.
Ex. Cigarette smoke

Question 10

Define:

Somatic cells & Gametes, are they haploid or diploid.

Answer 10

– 2 sets of chromosomes, NOT SEX CELLS, DIPLOID (2N)

–1 set of chromosomes, SEX CELLS, haploid (N)

Question 11

What causes cancer?

Answer 11

Failure to control cell division

Question 12

Difference between determination & differentiated?

Answer 12

Determination- cell gets to pick what cell type it will pick

Differentiated- cell is developed in specific cell

Question 13

Diploid cells have (2) sets of chromosomes, how many sets do you get from each parent?

Answer 13

One set from each parent

Question 14

Define

Malignant & Benign tumor

Answer 14

M/ BAD TUMOR, cells invade organs & continue to grow

B/ mass of abnormalities that remain at the original spot. (DO NOT SPREAD)

Question 15

What happens in Meiosis 1?

Answer 15

Same as mitosis, cells grow, CHROMOSOMES REPLICATE resulting in (2) haploid daughter cells.

Question 16

Name the phases of Meiosis 1, what happens in each phase?

Answer 16

• Interphase 1/ cells grow, DNA & proteins replicate, cell grow some more
• Prophase 1/ nuclear membrane breaks down, centrioles go to opposite ends, spindle fiber forms
• Metaphase 1/ chromosomes attach to spindle fibers & line in middle
• Anaphase 1/ chromosomes pull part & move to opposite ends of cell
• Telophase 1/ chromosome gather at pole, nuclear membrane forms, cytoplasm divides
• Cytokinesis 1/ cell becomes 2.

Question 17

Difference in homologous & non homologous chromosomes?

Answer 17

• Same # of genes along DNA

- different genes on DNA

Question 18

Meiosis involves gamete(sex cells) production, how many divisions does it go through?

Answer 18

- 2
Meiosis 1 (just like mitosis)
Meiosis 2 (cut in half)

Question 19

Name 5 factors that create genetic diversity by creating new alleles.

Answer 19

• Mutation/ change in nucleotide sequence in DNA
• Crossing over/ Exchange of equal portions of DNA between homologous chromosomes
• Segregation/ chromosomes broken apart randomly
• Independent Assortment/ half is going to one end, other half is going to other end
• Fertilization/ eggs & sperm unite

Question 20

What are the stages in Meiosis 2?

Answer 20

• Prophase 2/ nuclear membrane disappears, spindle fibers form
• Metaphase 2/ chromosomes line up in middle
• Anaphase 2/ centromeres divide, sister chromatids pull apart. Now called daughter chromosomes
• Telophase 2/ nuclear membrane forms, spindle fibers disappear, cell starts to pinch in middle
• Cytokinesis 2/ cells divide in 2

Question 21

Define:

• Monosomy

- Trisomy

Answer 21

• cell has (1) of a given pair of chromosome

- cell has (3) copies of given chromosomes

Question 22

What is Down syndrome?

Answer 22

• 3 copies of chromosome 21
• 47 chromosomes instead of 46
• symptoms inclement thickened eyelids, mental impairment, & faulty speech