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BIOLOGY REVISION > cell division, diversity and differentiation > Flashcards

cell division, diversity and differentiation Flashcards

1
Q

Give the 4 stages of the cell cycle.

A

M phase —- G1 phase—– S phase—– G2 phase

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2
Q

What section of the cell cycle is interphase?

A

Interphase is G1, S and G2 phase of the cell cycle, everything other than M phase

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3
Q

When does the G0 resting phase occur?

A

G0 rest phase occurs during or after G1

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4
Q

What happens in the G0 phase?

A

G0 is indefinite and within it apoptosis, differentiation and senescence can occur

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5
Q

What happens in G1 phase?

A

G1

  • cell increases in size
  • transcribe RNA
  • organelles duplicate
  • biosynthesis (protein synthesis)
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6
Q

What happen in S phase?

A

S phase

  • DNA replicates
  • commits cell to the cell cycle
  • rapid
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7
Q

What happens in G2?

A

G2

-Cell grows

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8
Q

What happens in M phase?

A

M phase

  • nuclear division
  • cytokinesis
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9
Q

Why does the cell cycle need regulating?

A

The cell cycle needs regulating in order to prevent uncontrolled division of cells and detect DNA damage.

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10
Q

What may happen is the cell cycle isnt regulated?

A

If the cell cycle isn’t regulated cancer may happen.

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11
Q

What does the regulation of the cell cycle ensure?

A

The regulation of the cell cycle ensures the cell cycle cannot be reversed and that DNA is only replicated once

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12
Q

What are the two main checkpoints and what is one event in each?

A

G2/M checkpoint produces chemicals to stimulate spindle forming proteins
G1/S checkpoint ensures the cell is ready for S phase

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13
Q

What is the G1/S phase checkpoint also known as?

A

G1/S Phase is also known as the RESTRICTION POINT

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14
Q

Give three reasons why mitosis is important

A

Mitosis is needed for asexual reprocution, growth and tissue repair

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15
Q

What are the 4 stages of mitosis and what occurs after?

A 
Prophase
Metaphase
Anaphase
Telophase
Interphase
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16
Q

What occurs in Prophase?

A 
Prophase:
-Nuclear envelope breaks down
-DNA supercoils
Centrioles divide into two centrioles
Tubulin threads/ spindle fibres form between centrioles
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17
Q

What occurs in Metaphase/

A

Metaphase:

-sister chromatid pairs attach to spindle by centromeres at the cell equator

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18
Q

What occurs in Anaphase?

A

Anaphase:

  • centromeres of chromatid pairs split
  • motor proteins drag chromatids to opposite poles
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19
Q

What happens in telophase?

A

Telophase:

-new nuclear envelope forms around the 2 sets of chcromsomes

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20
Q

What does cytokinesis do?

A

Cytokinesis splits the cell into 2 so that both contain a nucleus.

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21
Q

How does cytokinesis vary between animals and plant cells?

A

Cytokinesis in animal cells = pinches off after plasma membrane folds inwards
Cytokinesis in plant cells = an end plate forms where equator was and new plasma membrane and cellulose cell wall are laid down on either side

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22
Q

What cells do meiosis produce?

A

Mieosis produces 4 haploid cells

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23
Q

What is fertilastion

A

Fertilisation is the fusion of gametes nucei

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24
Q

What are siaster chromatids?

A

Sister chromatids are genetically identical chromosomes

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25
Q

What is the singificance of meiosis?

A

Meiosis itself produces genetic variation and it enables sexual reproduction which also increases genetic variation

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26
Q

What happens in prophase 1 ?

A

Prophase 1:

  • DNA super coiling
  • Nuclear envelope breakdown
  • Centriole division and spindles form
  • CROSSING OVER between homologous pair of chromosomes
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27
Q

What happens in metaphase 1?

A

Metaphase 1:

-Homologous chromosome pairs line up next to each other on the spindle equator

28
Q

What happens in anaphase 1?

A

Anaphase 1:

  • Chromosome from each pair is pulled to opposite poles
  • allele shuffling as the crossed over areas of homologous pairs separate from each other
29
Q

What happens in Telophase 1?

A

Telophase 1:

  • New nuclear enevelopes develop
  • cell may divide by cytokinisis
30
Q

Does telophase 1 happen in plan or animal cells?

A

Telophase 1 only occurs in animal cells, most plants move straight from anaphase 1 to prophase 2

31
Q

What happens in prophase 2?

A

Prophase 2:

  • nuclear envelopes breakdown
  • DNA supercoils and condenses
  • spindle formation
  • Chromatids are no longer identical
32
Q

What happens in metaphase 2?

A

Metaphase 2 :

  • randomly arranged chromosomes
  • chromosome attached by centromere to spindle equator
33
Q

What happens in anaphase 2?

A

Anaphase 2

  • Centromeres divide
  • chromatids of each chcormosome are puled apart by motor proteins
  • Random chromatid segregation
34
Q

What happens in telophase 2?

A

Telophase 2:

-Nuclear enevelopes form around eahc haploid nuclei

35
Q

What does telophase 2 result in in animals and plants?

A

In plants telophase 2 results in 4 haploid cells and in plants there is a tetrad; 4 haploid cells staying associated to each other.

36
Q

How does meiosis produce genetic variation?

A

Meiosis produdces genetic variation by:

  • crossing over in prophase 1 shuffles alleles
  • Anaphase 1 has independent assortment of chromosomes
  • anaphase 2 independent assortment of chromatids
  • random fertilisation
37
Q

What is differentiation?

A

Cell differentiation is the process by which stem cells become specialised into different types of cell. Genes are switched on or off

38
Q

What are 3 effects differentiation can have?

A

Differentiation:

  • alters the cells proportions of organelles
  • alter cell shape
  • alter contents of the cell
39
Q

What is the structure of a leaf?

A
  • waxy cuticle
  • upper epidermis
  • palisade mesophyll
  • spongy mesophyll
  • lower epidermis—stomata—-guard cells
  • waxy cuticle
40
Q

What re some features of palisade mesophyll cell?

A

Palisade mesophyll cells have a LARGE VACUOLE which pushes chloroplasts to the periphery of the cells to shorten diffusion distance. The chloroplasts can be moved by MOTOR PROTEINS along CYTOSKELTON threads depending on light levels

41
Q

How do guard cells open their stomata?

A

Guard cells:

  1. chloroplasts generate light energy to make ATP
  2. ATP actively transports K+ ions into the guard cells
  3. this lowers water potential so water moves in by osmosis
  4. influx of water makes guard cells swell pushing them out which opens the stomata
42
Q

Where are root hair cells found?

A

Root hair cells are epidermal cells on the outer layer of young plant roots

43
Q

What are some features of root hair cells?

A

Root hair cells have a LARGE SURFACE AREA for absorption and lots of MITONDRIA for the active pumping of ions into the cell. they also have CARRIER PROTEINS for the ions

44
Q

Very basic what are xylem and phloem?

A

Xylem and phloem are plant vascular tissue

45
Q

What are 3 types of plant tissue?

A

Plant tissues:

  • Vascular
  • meristematic
  • epidermal
46
Q

How is the xylem formed?

A

Formation of xylem from CAMBIUM: LIGNIN is deposited into cell walls which waterproofs, reinforces and kills cells. The ENDS OF CELL WALLS BREAK DOWN creating a continuous column

47
Q

How is phloem formed?

A

Formation of phloem from CAMBIUM: they LOSE ORGENELLES and their CYTOPLASM becomes very thin. SIEVE PLATES form between cells and COMPANIAN CELLS retain their organelles to produce ATP needed by sieve tube

48
Q

Describe meristematic tissue.

A

Meristematic tissue is tissue in the plant that has stem cells. there is meristematic tissue in shoots, roots and cambium. It has thin cell walls, no chloroplasts and a small vacuole. It can undergo mitosis

49
Q

What are 4 plant organs?

A

Flower- reproduction
Leaves- photosynthesis
Stem- support and transport
Roots- anchor, storage and absorption

50
Q

Discuss erythrocytes

A

Erythrocytes are specialised cells in the blood that carry O2 from lungs to respiring tissues. They are SMALL, have a LARGE SA:V and have a BICONCAVE shape. They lose most organelles to MAKE ROOM FOR HB and are FLEXIBLE to fit through capillaries

51
Q

Discuss neutrophils

A

Neutrophils are specialised cells in the blood that ingest invading pathogens. They have a MULTILOBED NUCELUS and are TWICE THE SIZE of erythrocytes. They are attracted to sites of infection by CHEMOTAXIS

52
Q

Discuss the structure of a spermatazoon

A

Spermatazoons:

  • haploid nucleus
  • acrosome
  • many mitochondria near tail to make atp to make tail move
  • undulipodium (tail)
53
Q

Desctibe epithelial cells.

A

Epithelial Cells are squamous and sometimes have projections like cilia. they line surfaces and

  • the cells are in close contact joined by lateral contacts. -They have a short cell cycle to replace damage
  • have no blood vessels.
54
Q

What are 4 tissue types in animals?

A

Animal Tissue types:

  • Muscle
  • connective
  • nervous
  • epithelial
55
Q

What are 3 types of muscle tissue?

A

Muscle tissue types:

  • Skeletal packaged by connective tissue+ has tendons
  • Smooth propels substances
  • Cardiac in heart
56
Q

What are lateral contacts?

A

Lateral contacts join close epithelial cells and are either tight junctions or desmosomes

57
Q

What is connective tissue?

A

Connective tissue is a non living extracellular matrix that separates living cells in tissues and enables them to withstand force. It is blood, cartilage , bone etc

58
Q

Discuss cartilage

A

Cartilage is connective tissue.

  • Chondroblasts are immature cells that secrete the extracellular matrix and divide by mitosis. They mature into chondrocytes
  • Chondrocytes maintain the matrix
59
Q

What are 3 types of cartilage?

A

Cartilage types:

  • Hyaline at ends of long bones, embryonic skeleton and nose, trachea etc
  • Fibrous at the knee joint and in discs between vertebrae
  • Elastic makes up the inner ear and the epiglottis
60
Q

Give 3 organ systems in animals

A

-Integumentary (hair, skin, nails) Immune, Endocrine, reproductive, digestive, circulatory, urinary, lymph, respiratory, musculoskeletal

61
Q

What are stem cells?

A

Stem cells are a renewing source of undifferentiated cells what are unspecialised so are able to express all of its genes

62
Q

What are the levels of potency

A

Totipotent - cells may become any cell (zygote)
pluripotent- can differentiate into almost any types of cells of the organism (embryo)
Multipotent- can differentiate into a limited number of cells (adult)
Unipotent- can differentiate into a single type of cell

63
Q

What potency are stem cells?

A

Stem cells are pluripotent

64
Q

What are 4 sources of stem cells?

A

Sources of stem cells:

  • Adult stem cells in blood, brain, muscles, bone, skin
  • umbilical cord blood
  • embryonic
  • induced pluripotent stem cells (reprogramming adult cells)
65
Q

What are 4 uses of stem cells?

A

Uses of stem cells:

  • Bone marrow transplants (blood diseases, cancer and immune system diseases)
  • Drug research
  • Developmental biology
  • repair of damage/lost tissue (includes regenerative medicine)
66
Q

What is regenerative medicine?

A

Using a bio-scaffold and populating it with stem cells so it grows into a specific shape to get someone a new organ OR populating an area of lost tissue with stem cells so the tissue gets replaced.

67
Q

How is bone marrow used to treat cancer?

A

Take the bone marrow out before treatment and then out it back in after.

BIOLOGY REVISION (21 decks)

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