Quiz #2: labs 3,6,11,12

Question 1

Electron microscopy

Answer 1

Use beams of electrons to magnify a specimen. Capable of magnifying objects many more times than the human eye can.

Question 2

When should an oil-immersion objective be used?

Answer 2

For observing small organisms and the fine detail of specimens

Question 3

Why do many biologists prefer a phase contrast microscope?

Answer 3

It has a special condenser for accenting tiny differences in a specimen, which is good for cellular components and microscopic organisms

Question 4

Advantage of parfocal objectives

Answer 4

Parfocal objectives only need small adjustments in focusing

Question 5

resolving power

Answer 5

depends on design and quality of objective lenses

Question 6

movement of protozoans in pond water in relation to movement of the slide

Answer 6

when the slide goes left, the protozoans move right, a mirror image.

Question 7

relationships between plane of focus, depth of field, illumination, and magnification

Answer 7

• a plane of focus puts the specimen at optimal distance
• depth of field is the thickness of the specimen-
• illumination lights the object
• magnification is the product of the power of the ocular and the power of the objective.
• all these things are used to examine a specimen

Question 8

what is the magnification of a microscope with a 10 x ocular and a 95 x oil-immersion objective?

Answer 8

ocular: 100x; oil-immersion: 950x

Question 9

three rules when focusing a microscope

Answer 9

1. adjust the oculars
2. raise the stage all the way up and position the specimen under the objective
3. use the focus adjustment knobs to get a clear view of the specimen

Question 10

Prokaryotic vs. eukaryotic cells

Answer 10

Prokaryotic cells do not have membrane-bound nucleus and organelles, while eukaryotic cells do. Prokaryotic organisms are in Archeabacteria and Eubacteria kingdoms; eukaryotic cells are in kingdoms protista, plantae, fungi, and animalia

Question 11

unicellular, colonial, multicellular organisms

Answer 11

• One cell: unicellular.
• colonial organisms: composed of loosely connected groups of cells
• multicellular: made from many cells

Question 12

What factors prevent cells from becoming the size of giant blobs that consume city blocks in science fiction movies

Answer 12

cells can only come from pre-existing cells

Question 13

compare and contrast plant and animal cells

Answer 13

plant cells: cell wall provides protection in shape. animal cells: plasma membrane provides the protection. in animal cells, lysosomes are used for digestive enzymes

Question 14

what is the significance of the S phase of interphase?

Answer 14

each chromosome replicates to produce two sister chromatids

Question 15

differences between animal and plant mitosis

Answer 15

animal cells: have abstula and during cytokinesis, a cleavage furrow develops.
plant cells: cell growth occurs in meristematic region and a cell plate is formed during cytokinesis

Question 16

how do the events that occur in interphase prepare the cell for prophase?

Answer 16

the chromosomes and the volume of the cell have doubled, allowing prophase to begin the process of cell replication

Question 17

difference between karyokinesis and cytokinesis

Answer 17

karyokinesis: division of genetic material
cytokinesis: division of the cytoplasm

Question 18

function of cell division

Answer 18

1. asexual reproduction
2. formation of gametes
3. growing and repairing tissues in animals

Question 19

what is meiosis?

Answer 19

the process of dividing sex cells

Question 20

what cells undergo meiosis?

Answer 20

gametes

Question 21

define and describe diploid (2n)

Answer 21

total number of chromosomes in the nucleus of a cell

Question 22

define and describe haploid (n)

Answer 22

one-half the number of pairs of chromosomes

Question 23

define and describe synapsis

Answer 23

process where homologous chromosomes pair up

Question 24

define and describe crossing over

Answer 24

physical exchange of genetic material between homologous pairs

Question 25

describe each stage of meiosis

Answer 25

meiosis I and meiosis II. In meiosis I, homologous chromosomes pair up in prophase I and exchange genetic material before the cell divides. Meiosis II is much like mitosis in that it has the same stages and processes like mitosis.

Question 26

events of spermatogenesis

Answer 26

A sperm cell undergoes meiosis I, which creates two sperm cells, then undergoes meiosis II, where the two cells divide and become sperm.

Question 27

where does spermatogenesis occur?

Answer 27

seminiferous tubules in the testes

Question 28

events of oogenesis

Answer 28

a primary oocyte divides in meiosis I into a secondary oocyte and a polar body. a sperm contacts the secondary oocyte, and meiosis II begins. it becomes a zygote

Question 29

where does the process of oogenesis begin?

Answer 29

ovaries

Question 30

what are polar bodies

Answer 30

result from unequal division of the cytoplasm

Question 31

compare and contrast meiosis

Answer 31

mitosis involves a division of the somatic cells. meiosis involves reduction or division resulting in the formation of sex cells

Question 32

what is the evolutionary significance of meiosis

Answer 32

allows for unique individuals that inherit hopefully beneficial traits from past generations