B1 - Cell Structure And Organisation Flashcards

1
Q

E. Magnification

A

Magnification= image size / size of real object

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2
Q

Function of cytoplasm?

A

Liquid gel where organisms are suspended and most chemical reactions for life take place.

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3
Q

Function of ribosomes?

A

Site of protein synthesis

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4
Q

Function of mitochondria?

A

Site of aerobic respiration

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5
Q

Function of cell membrane?

A

Controls the passage of substances in and out of the cell.

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6
Q

Function of chlorophyll?

A

Absorbs light so plant can make food by photosynthesis

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7
Q

Give a feature of a eukaryotic cell

A

Genetic material is enclosed in a nucleus

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8
Q

Give a feature of a prokaryotic cell

similar to the eukaryotic cell feature

A

Genetic material is not enclosed in a nucleus (free floating in the cytoplasm).

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9
Q

What are plasmids?

A

Small rings of DNA that code for specific features such as antibiotic resistances

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10
Q

Bacteria are….

A

Prokaryotic cells

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11
Q

Examples of specialised cells?

A

Nerve cells, muscle cells, sperm cells, red blood cells, ciliated epithelial cells, root hair cells etc etc

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12
Q

How are nerve cells specialised? (3)

A
  • Lots of dendrites that make connections to other cells
  • Axons that carry the impulse from one place to another
  • Synapses are adapted to pass the impulse to another cell or between a nerve cell and a muscle cell
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13
Q

How are muscle cells specialised? (3)

A
  • Contain proteins that slide over each other and make the fibres contract
  • Contain many mitochondria to provide the energy needed for chemical reactions to take place
  • Store glycogen, which can be broken down and used in cellular respiration by the mitochondria to provide energy needed for the fibres to contract.
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14
Q

How are sperm cells specialised?

4

A
  • Long tail helps it to move
  • Middle section is full of mitochondria, which provide energy for the tail
  • Large nucleus contains genetic information to be passed on
  • Acrosome stores digestive enzymes to break down the outer layers of the egg
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15
Q

Specialised plant cells?

A

Root hair cells, photosynthetic cells, xylem cells and phloem cells

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16
Q

How are root hair cells specialised? (3)

A
  • Long and narrow, which increases the surface area for water to move into the cell
  • Permanent vacuole that speeds up movement of water by osmosis from the soil across the root hair cell
  • Many mitochondria to transfer energy needed for active transport of mineral ions into the cells
17
Q

How are photosynthetic cells specialised? (3)

A
  • Contain specialised chloroplasts containing chlorophyll which absorbs the sunlight needed for photosynthesis
  • Usually positioned in continuous layers in the leaves and outer layers of the stem so they absorb as much light as possible
  • Large perm vacuole that keeps the cell rigid as a result of osmosis when lots of these rigid cells are arranged together, they help support the stem.
18
Q

How are xylem cells specialised? (2)

A
  • Alive at first but die and form long hollow tubes to allow water and mineral ions to move easily through them
  • Spirals and rings of lignin make them very strong and help them to withstand pressure of water.
19
Q

How are phloem cells specialised? (2)

A
  • Call walls between the cells break down to form special sieve plates. Allow water carrying dissolved food to move freely
  • Supported by companion cells which transfer energy and support them.
20
Q

D. Diffusion

A

The spreading out of the particles of gas of any substance in a solution ( a solute)

21
Q

Net movement of diffusion ?

A

From high to low concentration, down the conc gradient

22
Q

What effects the rate of diffusion?

A

Difference in concentrations, the temperature and the available surface area

23
Q

How do substances such as urea and glucose and gases such as oxygen and carbon dioxide move out and into cells?

A

Diffusion

24
Q

D. Osmosis?

A

The movement of water to dilute a solution across a partially permeable membrane, Down the conc gradient

25
Q

D. Isotonic?

A

The concentration of the solution is the same inside and outside the cell

26
Q

D. Hypertonic?

A

Solution conc is higher OUTSIDE the cell

27
Q

D. Hypotonic

A

Conc of solution is higher INSIDE the cell

28
Q

Why is osmosis important in plants?

A

To maintain turgor ( turgidity )

29
Q

Plasmolysis?

A

When the vacuole and cytoplasm shrink and the cell membrane is pulled away from cell wall

30
Q

D. Active transport?

A

The movement of substances from a dilute solution to a more concentrated solution against the concentration gradient

31
Q

Where does active transport occur? (2)

A
  • Small intestine - uptake of sugar

* In the roots (root hair cells)

32
Q

As the object gets bigger…

A

The surface area:volume ration decreases

33
Q

Why do most exchange surfaces usually have a large SA and thin walls?

A

To give a short diffusion distance.

34
Q

Differences between prokaryotes and eukaryotes? (3)

A

pro’s are….

  • smaller
  • don’t have a nucleus
  • may have plasmids