Lectures 9-12 (Exam 3)

Question 1

Mitosis

Answer 1

How non-sex (somatic) cells are generated - identical to each other

Question 2

Meiosis

Answer 2

How sex cells (gametes) are generated - not identical to each other

Question 3

Unicellular organisms

Answer 3

Binary fission or meiosis

Question 4

Multicellular organisms

Answer 4

Meiosis and mitosis

Question 5

Chromatin

Answer 5

DNA and protein that condenses during cell division

Question 6

Chromosome

Answer 6

1 DNA molecule

Question 7

Somatic cells

Answer 7

Non-sex cells - 2 sets of chromosomes (diploid) - 46 chromosomes

Question 8

Gamete

Answer 8

Sex cells (eggs/sperm) - 1 set of chromosomes (haploid) - 23 chromosomes

Question 9

Centromere

Answer 9

Where the sister chromatids are held together

Question 10

Dilpoid

Answer 10

Normal number of chromosomes in somatic cells (2)

Question 11

Haploid

Answer 11

Normal number of chromosomes in gametes (1)

Question 12

Interphase

Answer 12

Cellular contents double - cells spend most time here

Question 13

Prophase

Answer 13

DNA highly condenses, mitotic spindles form from centrosomes

Question 14

Prometaphase

Answer 14

Nucleus disappears, mitotic spindles extend across the cell - sister chromatids start attaching to mitotic spindles at kinetochores

Question 15

Metaphase

Answer 15

All sister chromatids are attached to mitotic spindles and line up in middle of cell

Question 16

Anaphase

Answer 16

Sister chromatids are pulled apart from one another

Question 17

Cytokinesis and telophase

Answer 17

Nucleus re-forms, mitotic spindles disappear

Question 18

Mitotic spindles

Answer 18

Microtubules (proteins) extended across cell - sister chromatids can attach to them

Question 19

Density - division signal

Answer 19

Dependent inhibition; crowded cells stop dividing - lost by cancer

Question 20

Anchorage dependence - division signal

Answer 20

Must be attached to a substrate in order to divide - lost by cancer

Question 21

Cancer cells

Answer 21

Cells that do not respond normally to the body’s control mechanisms - start out normal, undergo genetic mutations

Question 22

Tumor

Answer 22

Mass of abnormal growth cells

Question 23

Benign tumors

Answer 23

Remain at the original site but may disrupt organs if they grow

Question 24

Malignant tumors

Answer 24

Cancer - can spread to other location in a process called metastasis

Question 25

What can cancer therapies target?

Answer 25

Rapidly dividing cells - target the DNA (ionizing radiation/chemotherapy)

Question 26

Homologous pairs

Answer 26

Two chromosomes; one from mom and one from dad - produce different variations

Question 27

Autosomes

Answer 27

22 non-sex chromosomes

Question 28

Sex chromosomes

Answer 28

XX - female XY - male X - bigger Y - smaller eggs - always X sperm - X or Y

Question 29

How many chromosomes do we get from each of our parents?

Answer 29

23

Question 30

Meiosis characteristics

Answer 30

DNA replication 2 rounds of cell division 4 daughter cells

Question 31

Major sources of genetic information

Answer 31

Chromosomal arraignment during metaphase 1 Crossing over Joining of gametes (random fertilization)

Question 32

Nondisjunction

Answer 32

Failure of chromosomes or chromatids to separate normally during meiosis - fertilization after nondisjunction yields zygotes with altered #s of chromosomes

Question 33

Down syndrome

Answer 33

Example of nondisjunction - total chromosomes: 47, extra 21st chromosome

Question 34

Triploid syndrome

Answer 34

Example of nondisjunction - one extra of each chromosome (3 of each) - total chromosomes: 69 - will either result in miscarriage or death within first year

Question 35

Kleinfelter's syndrome

Answer 35

Example of nondisjunction - XXY - both male and female

Question 36

Mendel

Answer 36

Pea plants - controlled mating to see what traits would be passed to offspring. Saw that parents would breed (PxW), produced 100% P, bred the offspring, they produced 3/4 P, 1/4 W... etc.

Question 37

How did Mendel do his research?

Answer 37

Cut off stamens of one true-breeding variety, introduced pollen of another true-breeding variety to create self-fertilization between the plants

Question 38

Mendel's laws

Answer 38

Law of segregation - Punnett square Law of independent assortment

Question 39

Pleitropy

Answer 39

Most genes affect more than one trait (ex. sickle-cell anemia)

Question 40

Epistasis

Answer 40

A gene at one locus alters the phenotypic expression of a gene at a second locus

Question 41

Recessively inherited diseases - RIDs

Answer 41

Sickle-cell anemia, Huntington's disease, Cystic fibrosis

Question 42

Nuclear transplantation

Answer 42

Nucleus of an egg cell is replaced by the nucleus of an adult somatic cell

Question 43

Steps of nuclear transplantation

Answer 43

1. The nucleus is removed from an egg cell 2. A somatic cell from an adult donor is added 3. The cell grows in culture to produce a blastocyst 4. The blastocyst is implanted in a surrogate mother 5. A clone of the donor is born

Question 44

Embryonic stem cells vs. adult stem cells

Answer 44

Embryonic: can differentiate into any other cell type Adult: can only differentiate into blood cells