Principles Of Biology

Front 1

alleles of a gene are found at _____ chromosomes

Back 1

the same locus on homologous

Front 2

at the start of anaphase of mitosis,

Back 2

sister chromotids seperate

Front 3

during which phase of mitosis do the chromosomes line up on a plane equal distance from the two poles?

Back 3

metaphase

Front 4

during which stage of meiosis does crossing-over occur?

Back 4

prophase I

Front 5

looking into your microscope, you spot an unusual cell. instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. it sort of looks like the number 8. The you realize that the cell is

Back 5

undergoing cytokinesis

Front 6

prior to mitosis, each chromosomes of a eukaryotic cell consists of a pair of identical structures called

Back 6

sister crhomatids

Front 7

you are asked to culture an unidentified sample of animal tissue. you notice that the cells seem not to exhibit density-dependent inhibition. which of the following choices would be the most likely source for this tissue sample?

Back 7

a cancerous tumor

Front 8

when animals cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. this arrest of division is an example of

Back 8

density-dependent inhibition

Front 9

which of the following occurs during interphase?

Back 9

cell growth and duplication of the chromosomes

Front 10

which of the following statements are FALSE

Back 10

gametes are made by mitosis

Front 11

which of the following statements regarding the differences between mitosis and meiosis is FALSE? and why?

Back 11

Meiosis provides for asexual reproduction; meiosis provides for sexual reproduction, mitosis is asexual, Mitosis provides for growth and tissue repair, in mitosis, the chromosomes replicate only once in the preceding interphase, and all the events unique to meiosis occur during meiosis 1.

Front 12

which of the lists below correctly identifies the mitotic phases for the labeled cell?

Back 12

1= metaphase

2= interphase

3= telophase

4= anaphase

5 = prophase

Front 13

Define fertilization

Back 13

union of sperm and egg resulting in zygote

Front 14

cell Division is used for:

Back 14

- reproduction of single-celled organisms

- growth of multicellular organisms from a fertilixed egg into an adult

- repair and replacement of cells

- sperm and egg production

Front 15

define asexual reproduction

Back 15

produces offspring that are identical to the original cell or organism and involves inheritance of all genes from one parent

Front 16

define sexual reproduction

Back 16

produces offspring that are similar to the parents, but show variations in traits and involves inheritance of unique sets of genes from two parents.

Front 17

how is meiosis and mitosis different?

Back 17

Meiosis: 2 chromosomes divisions, homologous chromosomes, crossing-over, get 4 genetically different cells- haploid, 1/2 chromosome number

mitosis: get 2 genetically identical cells- diploid, same chromosome number

Front 18

how is meiosis and mitosis the same?

Back 18

each have one chromosome duplication

Front 19

human diploid cells have.....

Back 19

46 chromosomes = 2 sets 22 pairs of autsomes

Front 20

human haploid cells have.......

Back 20

23 chromosomes

Front 21

what is chromatin?

Back 21

DNA and protein in extended form (about 2 meters long stretched out); it helps maintain the chromosomes structure and control the activity of its genes, to prepare for division, the chromatin becomes: highly compact and visible with a microscope

Front 22

When a cell divides, the sister chromatids seperates from each other this is called

Back 22

chromosomes

Front 23

what is the cell cycle?

Back 23

it is a sequence of events from the time a cell is first formed from a dividing parent cell until its own dividsion

Front 24

the two stages of cell cycle is?

Back 24

1. interphase

2. mitotic phase

Front 25

interphase

Back 25

duplication of cells contents

a. G1 - growth, increase in cytoplasm

b. S (synthesis) - duplication of chromosomes

c. G2- growth, preparation for division

Front 26

Mitotic phase

Back 26

division (2 daughter cells)

a. mitosis - division of the nucleus

b. Cytokinesis - dividion of the cytoplasm

Front 27

What happens in cytokinesis?

Back 27

occurs along with telophase Cytoplasm dividion (cleavage furrow)

Front 28

What happens in interphase?

Back 28

G1 - cells grow, more organelles are produced, cytoplasm increases in volume

S - cell duplicates DNA

G2 - cells make sure chromosomes and organelles are ready for mitosis ( cell spends most of its time here)

Front 29

What happens in metaphase?

Back 29

Mitotic spindle formed, sister chromosomes align on metaphase plate

Front 30

what happens in prometaphase?

Back 30

spindle microtubules join from opposite poles and join at kinetochores of sister chromatids. Nuclear envelope disappears

Front 31

What happens in prophase?

Back 31

mitotic spindle begins to form Duplicated chromosomes condense. chromosomes coil and become compact and nucleoli disappear

Front 32

what happens in telephase?

Back 32

nuclear envelope reforms, mitotic spindle disappears, chromosomes uncoil. the cell continues to elongate and its prophase in reverse.

Front 33

what happens in anaphase?

Back 33

sister chromatids seperate, chromosomes move to opposite poles, centromere first ("V")

Front 34

in animal cells, cytokinesis occurs as?

Back 34

a cleavage furrow; it forms from a contracting ring of microfilaments

Front 35

in plant cells, cytokinesis occurs as?

Back 35

a cell plate; it forms in the middle. from vesicles containing cell wall material

Front 36

Cell division is controlled by?

Back 36

- Growth factors, proteins that stimulate division

- density-dependent inhibition, which crowded cells stop dividing

- anchorage dependence, the need for cells to be in contact with a solid surface to divide; the presence of essential nutrients

Front 37

Prokaryotes (bacteria and archaea) reproduce by binary fission ("dividing in half")

Back 37

the chromosome of a prokaryote is a singular circular DNA molecule associated with proteins and much smaller than those of eukaryotes

Front 38

Binary fission of prokaryote occurs in three stages:

Back 38

1. the cell replicates (duplicate) its single chromosome

2. the chromosome copies more apart & the cell elongates

3. the plasma membrane grows inward, dividing the parent into two daughter cells

Front 39

Eukaryotic cell division

Back 39

1.each chromosome appears as 2 sister chromatias, each containing identical DNA molecules

2. sister chromatids are joined at the centromere, a narrow region

- when a cell divides, the sister chromatids seperate

Front 40

the cell cycle control system

Back 40

a set of molecules in the cell that triggers and coordinates events of the cell cycle.

checkpoints in the cell can stop and event or signal an event to proceed.

Front 41

nondisjunction occurs when

Back 41

members if a chromosome pair fail to seperate

Front 42

which of the following statements regarding the cell cycle control system is FALSE? and why?

Back 42

the cell cycle control system operates independently of growth factors. because the cell cycle control system receives messages from outside and inside the cell, triggers and controls major events in the cell cycle, and includes three key checkpoints to complete a cell cycle.

Front 43

which of the following does NOT enhance genetic diversity? and why?

Back 43

mitosis of somatic cells. because it is random fertilization, crosses over during meiosis, and has independent orientation of chromosomes at metaphase I.

Front 44

abnormal cells that grow out of control

Back 44

1. Benign tumors: remain at the original state

2. malignant tumors: spread to other locations; harder to control and treat

3. Metastasis tumor: spread of cancer cells through the circulatory system

Front 45

Cancers named according to the organ or tissue in which they originate

Back 45

- Carcinomas: arise in external or internal body coverings

- Sarcomas: arise in supportive and connective tissue

- Leukemias and Lymphomas: arise from blood-forming tissues

Front 46

side effects of chemotherapy

Back 46

due to drug effects on normal cells that divide rapidly

- intestinal cells nausea

- hair follicle cells hair loss

- immune cell production infection

Front 47

what is the function of checkpoints in the cell cycle control system?

Back 47

make sure that each phase was completed properly

Front 48

What is a zygote?

Back 48

result of fertilization of egg by sperm