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science 9 > Science 9 - Chapter 5 Test > Flashcards

Science 9 - Chapter 5 Test Flashcards

0
Q

clone

A

identical genetic copy of its parent

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1
Q

Five major types of asexual reproduction used by organisms:

A
  1. binary fission (bacteria)
  2. budding
  3. fragmentation
  4. vegetative reproduction
  5. spore formation
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2
Q

budding

A

offspring starts as growth/bud on the body of the parent as a result of repeated mitosis and cell divisions

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3
Q

binary fission

A

organism splits in two roughly equal halves, pinches off (cytokinesis) to form two new organisms. mitosis not necessary because no nucleus in bacteria. single dna just replicates.

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4
Q

what does asexual reproduction mean?

A

without sex

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5
Q

how does asexual reproduction occur?

A

occurs without gametes (sex cells) coming together

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6
Q

how can asexual reproduction be characterized?

A

a. only one parent is required
b. no gametes (sex cells) required
c. offspring are clones (same set of chromosomes)
d. no specialized reproductive cells or structures

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7
Q

fragmentation

A

pieces of parent’s body breaks off. some fragments produce clones. sometimes occurs by accident. more often, it is deliberate.

ex: sea stars and flatworms reproduce by fragmentation

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8
Q

brain cells are replaced every:

A

30-50 years

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9
Q

stomach lining cells are replaced every:

A

2 days

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10
Q

skin cells are replaced every:

A

20 days

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11
Q

what are the 3 stages of the cell cycle?

A

interphase
mitosis
cytokinesis

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12
Q

interphase

A
  • cell increases in size, makes protein (carries out the functions necessary for survival)
  • cells copy/replicate itself and 3 billion base pairs of DNA information. DNA ladder break apart, new bases pair with bases on original DNA
  • cells make proteins for new daughter cells formed after cytokinesis. chromatin (containing replicated DNA) is loosely coiled. dna copied into rna. organelles duplicated. two new identical dna molecules produced
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13
Q

mitosis

A

divides the duplicated contents of the nucleus into two equal parts

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14
Q

cytokinesis

A

separates the two nuclei and cell contents into two daughter cells

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15
Q

early prophase

A
  • nucleolus disappears

- spindle fibres begin to form

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16
Q

late prophase

A
  • nuclear membrane disappears

- spindle fibres finish forming and attach to centromeres or chromosomes

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17
Q

metaphase

A
  • spindle fibres pull chromosomes into line at equator
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18
Q

anaphase

A
  • spindle fibres pull sister chromatids to opposite poles of cell
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19
Q

telophase

A
  • spindle fibres disappear
  • nuclear membrane forms around each separated set of chromosomes
  • nucleolus appears
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20
Q

define vegetative reproduction

A

only occurs in plants. form new plants without making seeds (without sexual reproduction)

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21
Q

how does vegetative reproduction work?

A

grasses, lilacs, and many forms send out rhizomes (underground stems.)

some woody shrubs reproduce asexually by using their ordinary stems, branches of these plants take root wherever they touch the ground.
ex: currants, willows, and forsythias

some plants send out runners which are special stems (they have a small, new, genetically identical plant on them.) when new plant touches ground; it roots, forming a whole new plant.
ex: strawberries and spider plants

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22
Q

grafting

A
  • does not happen naturally. humans must make this happen.

- stems called sions are attached to the rooted stock of another species (quicker harvest)

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23
Q

disadvantages of vegetative reproduction

A
  • clones, or new plants, grow close to the parents (compete for same resource)
  • clones, or new plants are genetically identical. illness or disease could kill all of them
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24
Q

benefits to humans of vegetative reproduction

A
  • food source (e.g. potatoes)
  • increase yield & speed of harvest
  • produce crops with specific qualities:
    • taste/texture
    • storage/handling
  • form single-celled spores (specialized reproductive cells)
    • have a nucleus, cytoplasm, and protective covering
    • covering protects spore from physical damage/drying out
    • carried away from parent by wind/water. when spore lands in favourable environment, it develops into a new organism through mitosis.
25
Q

cytokinesis in plant cells

A

a cell plate forms

26
Q

cytokinesis in animal cells

A

the cell membrane pinches together

27
Q

in cytokinesis: the 2 nuclei are separated into ________________ that are ____________ the original cell.

A

2 daughter cells, identical to

28
Q

why do cells divide?

A
  • cells receive nutrients & removes waste through cell membrane
  • size of cell membrane determines how much can enter/leave the cell
  • cells grow –> volume increases more quickly than surface area
  • once cell is certain size, membrane can’t support contents anymore
  • cells must divide to reach favourable surface/volume ration
  • when they get too big they divide
29
Q

What is cloning?

A

cloning is the process of making a genetically identical organism through nonsexual means

30
Q

uses of human assisted cloning?

A
  • to save genetic information from endangered species
  • to mass-produce an organism with a desirable trait
    • (for example pine trees that are resistant to pine beetles)
31
Q

problems of reproductive cloning (adult DNA cloning)

A
  • only about 10% of clones survive
  • clone can be abnormally large/sized
  • clones have higher rates of cancer and infection
  • clones age faster than others
32
Q

reproductive cloning (adult DNA cloning)

A
  • produces a genetic duplicate of an organism
    • takes a nucleus from a cell (from the organism to be cloned) and puts it into an egg cell that has had the nucleus removed
33
Q

how is therapeutic cloning used?

A

to correct health problems

34
Q

what does therapeutic cloning require?

A

stem cells

  • cells that have not specialized yet –> have the potential to become different types of cells
  • can use adult stem cells or embryonic stem cells
35
Q

which are more desirable to use in therapeutic cloning? adult stem cells or embryonic stem cells? why?

A

embryonic are more desirable because they can be more types of cells

36
Q

how can stem cells be used?

A

to replace damaged cells in patients with diabetes, spinal injuries, or Parkinson’s disease

37
Q

phases of mitosis

A 
early prophase
late prophase
metaphase
anaphase
telophase
38
Q

stages of interphase

A
  • growth and preparation
  • DNA replication
  • continued growth and preparation
39
Q

when are activities within the cell monitored/controlled?

A

at specific stages/checkpoints

40
Q

what monitors cell activity. why?

A

special proteins at the checkpoints monitor the cell activity and send this information to the nucleus.

41
Q

when will cells not divide?

A
  • not enough nutrients to support cell growth
  • dna in nucleus not replicated
  • dna damaged

ex; chromosomes not attached to spindle fibres in metaphase, chromosomes not moved to poles in anaphase

42
Q

what cause mutations?

A

mutagens (viruses, x rays, ultraviolet light, and chemicals such as acetone in cigarettes.

43
Q

what happens when a cell is exposed to radiation during mitosis?

A

chromosomes fail to move to opposite poles of a cell during anaphase

44
Q

what if a mutation occurred in a gene producing instructions for a checkpoint protein?

A

cell cycle control will be lost. damaged cells may divide uncontrollably.

45
Q

what is cancer?

A

certain diseases that result from uncontrolled cell division

46
Q

difference healthy cells cancer cells

A

healthy cells: grow in single layer, stop dividing when they stop receiving messages from nearby cells

cancer cells: don’t respond to messages, begin to grow in multiple layers

47
Q

what happens to nuclei of cancer cells? why?

A

become large and abnormal because cell division no longer functions and chromosomes do not divide correctly.

48
Q

do cancer cells function as parts of your body?

A

no, cancer cells are not specialized, they do not make proteins for organ cells.

49
Q

why do cancer cells release chemicals to attract blood vessels?

A

blood vessels branch into tumour and deliver nutrients to it

50
Q

how do cancer cells spread?

A

tumour cells break away and are carried by blood vessels to new location where they divide and form new tumour

51
Q

what treatment are cancer researchers looking for?

A

drugs that work by blocking cel division in a cancer cell and preventing formation of tumours

52
Q

how many times can a human cell divide?

A

50 times

53
Q

what are embryonic cells? how long can they live for?

A

early stage cells of developing embryo. indefinitely.

54
Q

when/why do embryonic stem cells lose their “fountain of youth?”

A

once a cell becomes specialized

55
Q

enzyme in stem cells?

A

enzyme telomerase

56
Q

what does telomerase do?

A

stop chromosomes from tangling/fraying with other chromosomes

57
Q

how do cancer cells escape programmed cell death? what does this mean for their chromosomes at cells division?

A

90 percent of human cancer cells don’t turn off telomerase gene. telomere caps of chromosomes do not shorten during cell division (divide longer than regular cells.)

58
Q

what happens before mitosis?

A

DNA molecules that replicated during interphase join to form sister chromatids of a chromosome joined by a centromere

59
Q

three parts/phases of interphase

A
  • growth and preparation
  • DNA replication
  • growth and preparation continued

science 9 (8 decks)

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