Chapter 1- Cell biology Flashcards

1
Q

What is a cell?

A

The smallest unit of life that can live on its own. Cells make up all living organisms and their tissues.

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2
Q

What are the differences between eukaryotic and prokaryotic cells?

A
  1. Eukaryotic cells are much larger.
  2. Eukaryotic cells contain membrane-bound organelles, while prokaryotic cells do not.
  3. Eukaryotic cells keep their DNA in the form of chromosomes within a nucleus, whilst prokaryotic cells have their DNA loose in the cell.
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3
Q

Are animal and plant cells prokaryotic or eukaryotic cells?

A

Eukaryotic cells.

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4
Q

Is a bacterial cell prokaryotic or eukaryotic?

A

Prokaryotic.

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5
Q

Name five sub-cellular structures found in both animal and plant cells.

A

Cell membrane, ribosomes, Nucleus, Mitochondria, cytoplasm.

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6
Q

What is the cell membrane and its role?

A

It is a protective barrier around the outside of the cell. It controls which substances can pass in and out of the cell.

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7
Q

What is the cytoplasm and what is its role?

A

A jelly like liquid that fills the cell. It allows substances to dissolve and chemical reactions take place.

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8
Q

What is the role of the nucleus?

A

It contains the genetic material of the cell and so controls what the cell does.

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9
Q

What is the role of the mitochondria?

A

They carry out aerobic respiration, so provide energy for the cell to use in chemical reactions.

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10
Q

What is the role of the ribosomes?

A

They are the sight of protein synthesis ( where proteins are made)

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11
Q

Name 3 sub-cellular structures (organelles) that are found in plant cells but not in animal cells.

A

Cell wall, chloroplast and permanent vacuole.

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12
Q

In plants, what is the cell wall made of?

A

Cellulose

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13
Q

What is the role of the plant cell wall?

A

It provides strength and structure to the plant cell, preventing it from bursting or shrinking when water enters/leaves the cell via osmosis.

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14
Q

What does the permanent vacuole contain?

A

Cell sap (full of sugars salts and amino acids).

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15
Q

What is the role of chloroplasts?

A

Chloroplasts are the site of photosynthesis and so they make glucose for the cell.

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16
Q

What is chlorophyll?

A

A green substance that absorbs light for photosynthesis.

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17
Q

Name 7 sub-cellular structures (organelles) that are found in bacterial cells.

A

Cytoplasm, Cell membrane, Cell wall, plasmids, singular strands of DNA, may have flagella.

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18
Q

What is the role of the permanent vacuole?

A

A chemical store that helps with the support of the cell, giving it extra nutrients.

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19
Q

What are plasmids, and what are their role?

A

It contains additional genes, such as for antibiotic resistance.

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20
Q

What is the definition of magnification?

A

How many times larger an image seen through a microscope is compared to the real object

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21
Q

What is the role of a microscope?

A

To produce magnified images that you are unable to see with the human eye.

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22
Q

Define resolution

A

A measure of the microscope’s ability to distinguish between two points which are close together on an object.

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23
Q

How does a light microscope work?

A

Light passes through the specimen which is on the stage, this goes through two sets of lenses to your eye. These two lenses are called the eyepiece lens and the objective lens.

24
Q

What parts are there on a light microscope?

A

The base, the stage, the objective lens, the eyepiece lens, the arm, the nosepiece, the coarse adjustment knob and fine adjustment knob, the light and diaphragm.

25
Q

What is an electron microscope?

A

They use electrons instead of light to form an image. They have a higher magnification and resolution than light microscopes. They are more expensive.

26
Q

What is the magnifying power of a light microscope?

A

X2000

27
Q

Give 5 advantages of light microscopes (compared to electron microscopes).

A

They are cheaper, easy to use, easy to transport, they can use live specimens, you can see images in colour.

28
Q

Explain the main disadvantage of light microscopes (as compared to electron microscopes).

A

They have a lower magnification and resolution. You can also only see 2D images.

29
Q

What is the magnifying power of an electron microscope?

A

X1,000,000

30
Q

What is the main advantage of electron microscopes (compared to light microscopes)?

A

They can produce 3D images. They have a higher resolution and magnification.

31
Q

what is the order of measurements for magnification?

A

Nanometres, (nm) micrometres (um) milimetres (mm) metres (m) kilometers (km).

32
Q

How do you convert nanometers to micrometers?

A

Divide by 1000

33
Q

Micrometers to millimeters?

A

Divide by 1000

34
Q

Millimeters to meters

A

Divide by 1000

35
Q

Meters to kilometers?

A

Divide by 1000

36
Q

Micrometers to nanometers?

A

X 1000

37
Q

What is the equation for magnification?

A

Magnification = image size
——————
Actual size

(I AM )

38
Q

Define active transport

A

The movement of substances against a concentration gradient and/or across a cell membrane using energy.

39
Q

Define diffusion.

A

The net movement of particles of a gas or a solute from an area of high concentration gradient to an area of low concentration ( along a concentration gradient).

40
Q

Define osmosis.

A

The net movement of water from an area of high concentration to an area of low concentration, along a concentration gradient (the movement of water)

41
Q

Differences between diffusion, osmosis and active transport

A

Diffusion- movement of molecules/ ions from a high conc to a low conc down a conc gradient.

Osmosis- movement of water molecules from a high water potent to a low water potential, across a partially permeable membrane.

Active transport- Movement of particles of substances from a low conc to a high conc, against. Conc gradient. Energy is required.

42
Q

Differences between diffusion and active transport.

A

Diffusion does not require energy as it acts down a conc gradient. Active transport does require energy as it acts agains a conc gradient.

Active transport is a low conc gradient go a high, but diffusion is the other way around.

43
Q

What effects the rate of diffusion and why?

A

Two things, the type of substance- substances diffuse more quickly through gases than through liquids. This is because the particles in a gas are more spread out and move faster than the particles in a liquid.

Temperature- the hotter the substance, the faster diffusion happens, the particles have more energy and move faster at higher temperatures.

Surface area to volume ratio- the larger the surface area on the membrane, the faster the diffusion rate, because more particles can pass through at once,

44
Q

What effects the rate of osmosis and why?

A

Temperature- higher temp= faster particles move due to increase in kinetic energy, so the faster osmosis happens.

Concentration gradient- the higher the concentration gradient (the larger the difference in concentration) the faster the rate of osmosis. This also applies to diffusion and active transport.

45
Q

What effects the rate of active transport and why?

A

Temperature - same as others.

46
Q

Define supply rate.

A

area of the cell’s surface which determines the quantity of oxygen the organism can get.

47
Q

Define the demand rate of a cell.

A

The demand rate is the volume of a cell which determines the quantity of oxygen the organism can use. The ratio for this can be written as:
Surface area over volume

48
Q

How is diffusion, osmosis and active transport helpful to cells?

A

Diffusion- it is essential for cell respiration, it helps the movement of carbon dioxide that builds up inside out of the cell down the concentration grad, without using any of the energy from respiration.

Active transport- It helps bring in required nutrients and ions into the cell against the concentration gradient. It allows oxygen in and reduces waste.

Osmosis- It helps stabilize internal movement of water and intracellular fluid levels within a cell.

49
Q

Define isotonic

A

when a molecule attempts to become isotonic it refers to it having an even number of particles inside and outside of the cell; in other words, it essentially involves the molecules ‘spreading out’. When any molecule or ion attempts to become isotonic it is called moving across its concentration gradient.

50
Q

Define Hypertonic

A

Hypertonic solutions means the cell becomes smaller and shrinks, due to a higher solute concentration (thus lower water potential) outside of cell.

51
Q

Define hypotonic

A

Hypotonic solution means the cell becomes swollen and can potentially burst, due to a lower solute concentration (thus a higher water potential) on outside of cell.

52
Q

Define turgid within a plant cell

A

When plant cells are placed in a solution with a high water concentration compared to their contents, they will gain water by osmosis and swell up until their cytoplasm and cell membrane are pushing against their cell wall. They are now turgid.

53
Q

What prevents the plant cell from bursting?

A

The cell wall.

54
Q

Define plasmosis within a plant cell.

A

When Plant cells are placed in a solution with a low water concentration compared to their contents, they will lose water by osmosis.

Their cell membranes will peel away from their cell walls and they are said to be plasmolysed.

55
Q

How is osmosis different within plant cells compared to animal cells?

A

When too much water leaves a cell, a plant cell is able to remain the shape it is, because it has a cell wall.However, when too much water leaves an animal cell, the cell shrivels and shrinks.

56
Q

Where does active transport occur?

A

In the root hair cells, it takes in mineral ions and water by using energy from respiration.

Within humans, active transport allows nutrients to be taken into the blood, such as glucose where it can be transported and used for respiration.

57
Q

What are the required practicals for this section?

A

Microscopic practical and osmosis within potatoes.