B1 & B2.1 - Cells & Cell Division Flashcards

1
Q

What are the main characteristics of an Animal Cell?

A

Nucleus, Cytoplasm, inelastic, partially-partially-permable Cell Membrane, Mitochondria, Ribosomes

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2
Q

Cytoplasm

A

Liquid gel where organelles are suspended. This is where most of the chemical reactions needed for life take place.

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3
Q

Nucleus

A

Controls all the activities of the cell that contains genetic material, which carry instructions for making proteins needed to build new cells / organisms.

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4
Q

What are the main characteristics of a Plant Cell?

A

Components of an Animal Cell + Chloroplasts, Permanent Vacuole and Cellulose Cell Wall.

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5
Q

Cell Membrane

A

Controls passage of substances into the cell (glucose and mineral ions), as well as movement out of the cell (urea and hormones).

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6
Q

Mitochondria

A

Where aerobic respiration takes place, releasing energy for the cell.

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7
Q

Ribosomes

A

Where protein synthesis takes place, making all the proteins needed in the cell.

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8
Q

True or False?

Plant Cells do not contain all the characteristics of an animal cell (cell membrane, cytoplasm etc.)

A

False!
Plant Cells have all the features of a typical animal cell, but they also contain features that are needed for their very different functions.

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9
Q

True or False?

All plant and algal cells have a cell wall made of cellulose that strengthens the cell and gives it support.

A

True.

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10
Q

Chloroplasts

A

Contains chlorophyll, which makes chloroplasts green! Chlorophyll absorbs light for photosynthesis.

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11
Q

Permanent Vacuole

A

A space in the cytoplasm filled with cell sap. Important for keeping the cells rigid to support the plant.

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12
Q

True or False?

A plant cell has many features in common with an animal cell, as well as other features that are unique to plants.

A

True!

Plant Cells have added features, such as chloroplasts and a permanent vacuole.

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13
Q

True or False?

Roots cell contain chloroplasts because they are underground and need to photosynthesise.

A

False!
Because they are underground, they cannot absorb sunlight; a key component in producing their own food through photosynthesis. As a result, they do not have chloroplasts!

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14
Q

Define Prokaryotic

A

Pro- = Before / None

  • kary- = Karyon = Nucleus
  • Otic = State / condition

= A cell in which their genetic material is encased WITHOUT a nucleus, thus freely moving around in the cell.

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15
Q

Define Eukaryotic.

A

Eu - “Eureka” = True / Aha!

  • kary- = Karyon = Nucleus
  • Otic = state / condition of an entity

= A cell which has their genetic material encased WITH a nucleus.

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16
Q

Give an example of a Prokaryotic Cell.

A

Bacteria

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17
Q

Give an example of a Eukaryotic Cell.

A

Animal and plant cells!

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18
Q

What is a Eukaryotic cell?

A

Cells which all have a cell membrane, cytoplasm, and genetic material that is enclosed in a nucleus.

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19
Q

What is a Prokaryotic cell?

A

Much like eukaryotic cells, except their genetic material that is NOT enclosed in a nucleus, and may also contain extra small rings of DNA called plasmids.

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20
Q

What are plasmids?

A

Located usually in Prokaryotic cells (e.g. Bacteria), DNA which are codedfor very specific features such as antibiotic resistance.

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21
Q

What is a flagellum?

A

A long protein strand that lashes about to allow the cell to move around.

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22
Q

What effect does bacteria have on other organisms.

A

Little to no effect. Many are very useful.

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23
Q

Diffusion

A

Net movement of particles from an area of high concentration to an area of low concentration.

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24
Q

Effect of Diffusion

A

Usually results in equilibrium; same number of particles on each side.

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25
Q

Net Movement

A

Net movement = particles moving in - particles moving out

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26
Q

Why Diffusion is Passive

A

Doesnt need energy: particles move down the concentration gradient easily.

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27
Q

Factors affecting Diffusion

A

• Temperature:
higher temperature = more kinetic energy for particles to richochet/bounce off each other.
- Particles move around quicker consequently.

• Steeper Concentration Gradient:
Steeper gradient = greater net movement of particles.

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28
Q

Active Transport

A

Moving UP / against a concentration gradient, which needs energy.

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29
Q

Examples of Active Transport

A

• Nerve Cells:

Active transport of Sodium moving out and Potassium moving in the nerve cell.

• Root Hair Cells:

Magnesium ions actively transported into the root hair cell.

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30
Q

Difference between Active Transport & Diffusion

A
  • ATP (adenosine triphosphate) is needed for Active Transport.
  • Active Transport is going against the concentration gradient; lower concentrated particles moving to an area of higher concentration.
  • Diffusion doesn’t need energy.
  • Diffusion goes down the concentration gradient; higher concentrated particles moving to an area of lower concentration.
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31
Q

ATP

A

Adenosine Triphosphate

Adenosine
Tri-
Phosphate

32
Q

Carrier proteins

A

Special proteins that span a cell membrane width.

Molecules that a cell needs will bind with the carrier proteins.

As a result, ATP is needed to change or rotate the proteins if needed.

33
Q

Isotonic solution

A

External concentration of solutes [outside the cell] = Internal concentration of solutes [inside the cell]

34
Q

Hypertonic

A

External concentration of solutes [outside the cell] > Internal concentration of solutes [inside the cell]

35
Q

Hypotonic

A

External concentration of solutes [outside the cell] < Internal concentration of solutes [inside the cell]

36
Q

Cell Differentiation

A

The process for when a cell changes to become specialised for its role.

37
Q

Partially-permeable membrane

A

Membrane with tiny holes which allows small molecules to pass through, except large molecules.

38
Q

Undifferentiated cells

A

Stem cells

39
Q

Specialisation of Sperm Cells

A

Reproduction:

  • long tail-like flagellum and streamlined head to help it swim to the egg cell.
  • plentiful mictochronfria to provide needed energy
  • Enzymes in the head to digest through egg cell membrane.
40
Q

Specialisation of Nerve Cells

A

Rapid signalling:
- long length to cover more distance and have branched connections at their ends to connect to other nerve cells and form a network throughout the body.

41
Q

Specialisation of Muscle Cells

A

Contraction:

  • long lengths for space to contract
  • lots of mitochrondria to generate energy needed for contraction.
42
Q

Specialisation of Root Hair Cells

A

Absorbing water & minerals:

- long hair-like tube that stick out into the soil for a big surface area to absorb water and mineral ions.

43
Q

Most differentiation occurs…

A

…As an organism develops.

44
Q

Cells that differentiate in mature animals…

A

…Are mainly used for repairing and replacing cells, such as skin and blood cells.

45
Q

Specialisation of Phloem & Xylem Cells

A

Transporting Substances:

  • form phloem and xylem tubes respectively to transport food and water around plants.
    • to make these tubes, the cells are long and joined end-to-end.
  • Xylem tubes are hollow in centre,
  • Phloem have very few subcellular structures, so substances can flow through them.
46
Q

Turgor

A

The pressure that builds up when the inelastic cell wall of a plant cell resists expansion, and the cell becomes rigid or turgid.

47
Q

Plasmolysis

A

When water is lost from a plant cell through osmosis ie cells in a hypertonic solution;

  • the cell membrane pulls away from the cell wall.
48
Q

Why Osmosis is needed for turgor

A

Osmosis is key to maintaining turgor in plant cells, as it needs a rigid structure to protect their sub-cellular components.

49
Q

Difference(s) between Diffusion and Active Transport.

A

Active transport uses ATP ( Adenosine Triphosphate ), diffusion uses no energy - therefore active transport is active, diffusion is passive.

50
Q

What is osmosis, really?

A

The diffusion of water molecules.

51
Q

Why do animal cells, which are hypotonic, burst?

A

The cell membrane is not elastic enough to contain all the water.

  • Animal cells also don’t have cell walls, which plant cells have to keep their turgor.
52
Q

How do people die from ecstasy through water consumption?

A

Their animal cells, receiving an abnormal amount of water, become hypotonic. As a result, they burst.

  • The killing blow is due to brain cells becoming hypotonic and likewise, bursting. This kills the person.
53
Q

Water Potential

A

The measure of the tendency of the concentration % of water molecules to diffuse to another area.

54
Q

[Synoptic Link] Water potential, Pure Water, and Isotonic Solutions ( 1 / 2 )

A
  • Pure water has a water potential of 0, meaning water molecules will not diffuse to another area.
  • Similarly, in an isotonic solution, because the concentration of solutes are equal both internally in the cell and externally in the solution, water molecules will not diffuse to either area.
55
Q

[Synoptic Link] Water potential, hypertonic & hypotonic solutions ( 2 / 2 )

A
  • Water Potential measures the tendency of water molecules to diffuse to another area because of the concentration of solutes present internally [ in the cell ] and externally.
  • Within a hypertonic solution, because more solutes are present externally in the solution than internally inside the cell, water molecules will diffuse out the cell and into the solution.
  • In a hypotonic solution, more water molecules are present [than solutes] outside the cell in the solution than inside the cell, so water molecules diffuse into the cell.
56
Q

Negative number quantities in Water Potential

A

The greater the negative number is in reference to water potential in a solution or specimen, the less pure it is.

  • Thus, more solutes are present.
57
Q

[Synoptic Link] Pure Water and Water Potential

A

Pure water has a water potential of zero; water molecules will not diffuse to another area.

58
Q

Lysis; Hypotonicity

A

When a cell fills with water. Since the cell membrane is inelastic, the cell will burst unless it has a cell wall. The cell becomes lysed when it is exposed to a hypotonic solution.

59
Q

Crenation ; Hypertonicity

A

When water floods out an animal / body cell. The cell becomes crenated when it is exposed to a hypertonic solution.

60
Q

[Exchanging Materials] Unicellular organisms

A
  • High surface area : volume ratio.

- Can exchange materials directly with their environment through their cell membrane ( which is partially permeable! ).

61
Q

[Exchanging Materials] Multicellular organisms

A
  • Low surface area : volume ratio.
  • The surface areas of multicellular organisms aren’t large enough to exchange materials directly with their environment.
  • Consequently, they’ve evolved to be equipped with specially-adapted exchange surfaces and transport systems.
62
Q

Multicellular organisms’ evolutions examples for specially-adapted exchange surfaces and transport systems

A

Humans:
- Lungs and the Alveoli

Fish:
- Gills

Root Hair Cells

63
Q

The Cell Cycle: phases

A
  1. Interphase
  2. Prophase
  3. Metaphase
  4. Anaphase
  5. Telophase
  6. Cytokenesis
64
Q

Interphase, Prophase, …?…, Anaphase, Telophase, Cytokenesis.

What phase is missing?

A

Interphase, Prophase, METAPHASE, Anaphase, Telophase, Cytokenesis.

65
Q

[1] , [2] , [3] , Anaphase , [5] , [6] .

What’s missing?

A

INTERPHASE , PROPHASE , METAPHASE , Anaphase, TELOPHASE , CYTOKENESIS.

66
Q

… Anaphase , [5] , [6] .

What’s missing?

A

Anaphase, TELOPHASE , CYTOKENESIS

67
Q

Phases of the Cell Cycle:

[1] , [2] , [3] , [4] , [5] , [6] .

Complete the missing steps.

Hint: ___phase, ___phase etc.

A
[1] Interphase
[2] Prophase
[3] Metaphase
[4] Anaphase
[5] Telophase
[6] Cytokenesis

Well done if you remember!

68
Q

Mitosis

A

The main stage(s) at which a cell divides:

[3] Metaphase - The replicated chromosomes line up along the centre of the cell.

[4] Anaphase - The spindle fibres contract, and the chromosomes are pulled to opposites poles equally.

[5] Telophase - Cell membranes form around each of the sets of chromosomes, dividing the nucleus, and creating two new nuclei.

[6] Cytokenesis - The original cell has been fully divided into two daughter cells, both having identical DNA to each other and to the parent cell.

69
Q

[1] Interphase

A

DNA inside the cell is replicated to from copies of each chromosome and synthesis of new sub-cellular structures.

70
Q

[2] Prophase

A

DNA replication has occurred by now, and each chromosome is identical. The spindle fibres move to opposite sides of the cell.

71
Q

[4] Anaphase

A

The spindle fibres contract, and the chromosomes are pulled to opposites poles equally.

72
Q

[3] Metaphase

A

The replicated chromosomes line up along the centre of the cell.

73
Q

[5] Telophase

A

Cell membranes form around each of the sets of chromosomes, dividing the nucleus, and creating two new nuclei.

74
Q

Are Interphase and Prophase part of mitosis?

A

No.

[1] Interphase - DNA is replicated, not divided.

[2] Prophase - DNA replication has occurred by now, and each chromosome is identical. But the DNA isn’t divided yet.

Note: Prophase is when the DNA replication has finished which happened in the Interphase.

75
Q

[6] Cytokenesis

A

The original cell has been fully divided into two daughter cells, both having identical DNA to each other and to the parent cell.