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Biology 160 > BIO 160 Chapter 8 > Flashcards

BIO 160 Chapter 8 Flashcards

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1
Q

cell division

A

the two daughter cells that result are genetically identical to each other

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2
Q

asexual reproduction

A

does not involve the fertilization of an egg by a sperm

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3
Q

sexual reproduction

A

requires fertilization of an egg by a sperm

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4
Q

gametes

A

egg and sperm

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5
Q

meiosis

A

cell division which occurs in reproductive organs

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6
Q

histones

A

small proteins used to package DNA

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7
Q

nucleosome

A

are proteins used to package DNA in

eukaryotes

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8
Q

centromere

A

narrow “waist” that joins sister chromatids,holds the sister chromatids
together

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9
Q

cell cycle

A 
A cell cycle is the ordered sequence of events that 
lead to cell division
• Interphase
• Mitosis
– Prophase
– Metaphase
– Anaphase
– Telophase
– Cytokinesis
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10
Q

interphase

A

a time when a cell performs is normal functions within an organism

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11
Q

mitotic phase

A

part of the cell cycle when the cell is actually dividing

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12
Q

cytokinesis

A

the cytoplasm is divided into two

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13
Q

eukaryotic cells

A

• most genes are located on chromosomes in the cell
nucleus and
• a few genes are found in DNA in mitochondria and
chloroplasts.
• Nucleus contains lots of DNA and genes
• Number of chromosomes in a eukaryotic cell depends
species.

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14
Q

chromatin

A

fibers composed of roughly equal amounts
of DNA and protein molecules and
– not visible in a cell until cell division occurs

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15
Q

when is DNA replicated?

A

DNA is replicated during s-phase, resulting in

sister chromatids containing identical genes

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16
Q

what happens during interphase?

A

During interphase, a cell:
• Functions normally
• Duplicates everything in cytoplasm
• Grows in size

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17
Q

what happens during mitotic phase?

A

• Mitosis: when nucleus and its contents divide evenly
into 2 daughter nuclei
• Cytokinesis: when cytoplasm is divided into two

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18
Q

mitosis

A

– Results in two identical daughter cells
– Functions:
• replaces damaged or lost cells (tissue repair)
• permits growth (growth)
• allows for reproduction (asexual)

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19
Q

interphase

A

each chromosome replicates in late interphase, resulting in two sister chromatids connected at the centromere, chromosomes are loosely gathered at the nucleus

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20
Q

prophase

A

replicated chromosomes begin to coil up
nuclear membrane begins to disassemble
protein fibers of mitotic spindle begin to form

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21
Q

prometaphase

A

chromosomes condense to shorten them, making it easier to separate
spindle fibers attach to chromosomes on both sides at the centromere region

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22
Q

metaphase

A

spindle fibers from opposite sides begin to pull on chromosomes
chromosomes are aligned along middle of cell

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23
Q

anaphase

A

spindle fibers shorten and pull sister chromatids to opposite ends of the cell

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24
Q

telophase

A

an identical set of chromosomes reaches each pole
spindle fibers disassemble
nuclear membrane forms around each set of chromosomes, forming the daughter cell nuclei

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25
Q

cytokinesis

A

• During cytokinesis, the cell membrane pinches in to
completely surround each new daughter cell.
• The cell cycle starts over with two newly formed identical
daughter cells in interphase. Each daughter cell has the same
number of chromosomes as the parent cell

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26
Q

how does cytokinesis differ in plants and animals?

A

– In animal cells
• known as cleavage
• begins with the appearance of a cleavage furrow, an
indentation at the equator of the cell.
– In plant cells
• cytokinesis begins when vesicles containing cell wall
material collect at the middle of the cell and then fuse
– forms membranous disk called the cell plate.

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27
Q

What happens when cell cycle goes

out of control?

A

Specialized cell cycle factors normally regulate cell
proliferation by sending “stop” or “go”signals.
• Tumor suppressor genes lose ability to regulate cell
division
• Oncogenes gain ability to always be active

28
Q

Tumor suppressor genes

A

Tumor suppressor genes lose ability to regulate cell BRAKES

division

29
Q

oncogenes

A

Oncogenes gain ability to always be active GAS

30
Q

What is cancer?

A

– Uncontrolled cell proliferation
– Cancer cells can form tumors, abnormally growing
masses of body cells.
– If the abnormal cells remain at the original site,
the lump is called a benign tumor

31
Q

tumor

A

abnormally growing mass of body cells

32
Q

metastasis

A

The spread of cancer cells beyond their original

site of origin is metastasis

33
Q

malignant tumor

A

• spread to other parts of the body and
• interrupt normal body functions.
– Patients w malignant tumor have cancer

34
Q

cancer treatment

A

– Resection: removal of tumor
– Radiation therapy: damages DNA and disrupts cell
division
– Chemotherapy: uses drugs to disrupt cell division

35
Q

resection

A

removal of tumor

36
Q

radiation therapy

A

damages DNA and disrupts cell

division

37
Q

chemotherapy

A

uses drugs to disrupt cell division

38
Q

meiosis

A

– Results in four haploid gametes
– Functions:
• To increase genetic diversity (ie offspring have slightly
different genetic makeup compared to parents)
• Allows sexual reproduction
• Keeps the chromosome number from doubling every
generation.

39
Q

somatic cell

A

– A human somatic cell
• is a typical body cell
• has 46 chromosomes

40
Q

karyotype

A

A karyotype is an image that reveals an orderly

arrangement of chromosomes.

41
Q

homologous chromosome

A
  • are matching pairs of chromosomes

* can possess different versions of the same genes

42
Q

sex chromosomes

A

X or Y

43
Q

autosomes

A

matching chromosomes

44
Q

life cycle

A

The life cycle of a multicellular organism is the
sequence of stages leading from the adults of one
generation to the adults of the next.

45
Q

diploid organism

A

Humans are diploid organisms with
• body cells containing two sets of chromosomes
• Haploid gametes that have only one member of each
homologous pair of chromosomes

46
Q

diploid zygote

A

In humans, a haploid sperm fuses with a haploid egg

during fertilization to form a diploid zygote

47
Q

meiosis process

A

– Haploid daughter cells are produced in diploid
organisms.
– Interphase is followed by two consecutive
divisions, meiosis I and meiosis II.
– Genetic diversity increases through DNA
recombination (crossing over) and independent
assortment

48
Q

mitosis vs meiosis

A

– Chromosomes duplicate only once (in S-phase of
Interphase)
– The number of cell divisions varies:
• Mitosis: one division and produces two diploid cells.
• Meiosis: two divisions and produces four haploid cells.
– All the events unique to meiosis occur during
meiosis I.

49
Q

origins of genetic variations

A

– Offspring of sexual reproduction are genetically
different from their parents and one another.
– Mechanisms
• DNA recombination (Prophase I of Meiosis)
• Independent assortment (Metaphase I of Meiosis)
• Random fertilization

50
Q

DNA recombination

A

– In crossing over,
• nonsister chromatids of homologous chromosomes
exchange corresponding segments
• Genetic recombination, the production of gene
combinations different from those carried by parental
chromosomes, occurs

51
Q

independent assortment

A

• Homologous chromosomes align at Metaphase I
randomly
• Homologous chromosome pairs align independently of
other chromosomes
• Total number of chromosome combinations that can
appear in gametes due to independent assortment is 2
n
,
where n is the haploid number
– For humans: 2
23
, there are 8,388,608 different chromosome
combinations possible in a gamete

52
Q

random fertilization

A

• Fertilization between egg and sperm is random
• If each gamete is 1 in 8,388,608 different
chromosome combinations, humans have >70 trillion
(8,388,608x8,388,608) different chromosome
combinations

53
Q

nondisjunction

A

• Occurs when members of a chromosome pair fail to
separate at anaphase
• produces gametes with an incorrect number of
chromosomes
• Can occur during meiosis I or II

54
Q

what happens when errors occur in meiosis?

A

If nondisjunction occurs, and a normal sperm
fertilizes an egg with an extra chromosome, the
result is a zygote with a total of 2n + 1
chromosomes.
– If the organism survives, it will have
• an abnormal karyotype and
• probably a syndrome of disorders caused by the
abnormal number of genes.

55
Q

down syndrome

A

– Trisomy 21
– A condition where an individual has an extra
chromosome 21
– Affects ~1 in 700 children
– The incidence of Down syndrome in the offspring
of normal parents increases markedly with the age
of the mother.

56
Q

roles of cell division in living organisms

A

cells must divide to replace damaged or ost cells, growth and reproduction

57
Q

describe structure of a chromosome

A

helix. histones, nucleosome, centromere

58
Q

explain how and when chromosomes are duplicated

A

before the cell divides and DNA molecule is copied and proteins attach as needed, each chromosome consists of two copies called sister chromatids.

59
Q

describe key events of the cell cycle

A

interphase- doubles everything in cytoplasm, increases supply of proteins, increases number of organelles.. duplicates chromosomes
mitotic phase- 2 daughter nuclei formed
cytokinesis- cytoplasm splits

60
Q

s phase

A

DNA replication

61
Q

g phases

A

gap phases between s phase G1 G2

62
Q

how are tumor cells different than healthy cells of the body?

A

tumor abnormally growing in body, healthy cells have gas or brakes…

63
Q

benign vs malignant

A

benign stays at original site, malignant spreads to surrounding tissue

64
Q

slash burn and poison

A

remove tumor, radiate “burn” cells, poison, drugs used to disrupt cell division

65
Q

sex chromosomes vs autosomes

A

sex chomosomes, non matching pair,

autosome all match

66
Q

somatic cells vs gametes

A

somatic cells have 46 chromosomes somatics go through mitosis, gametes go through meiosis

67
Q

diploid vs haploid

A

diiploid - homologous chromosomes

haploid - a single chromosome set

Biology 160 (11 decks)

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