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Biology > B1 > Flashcards

B1 Flashcards

1
Q

Are light microscopes cheap or expensive ?

A

Relatively cheap

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2
Q

How do light microscopes work?

A

They use a beam of light to form the image of an object.

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3
Q

How much can a light microscope magnify?

A

They magnify things several thousand times.

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4
Q

How do electron microscopes work and what is they’re max magnification.

A

They use a beam of electrons to form an image and can magnify images up to two million times.

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5
Q

What are the two types of electron microscopes and explain what both are ?

A

Transmission electron microscopes give 2D images but very high magnification and resolution.

Scanning electron microscopes give 3D images but lower magnifications.

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6
Q

What type of cell makes up the body ?

A

Animal cells

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7
Q

What is a nucleus and what does it do?

A

A nucleus controls all the activities of the cell and is surrounded by the nuclear membrane. it contains the genes on the chromosomes that carry the instructions for making proteins needed to build new cells or new organisms. The average diameter is around 10 μm.

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8
Q

What is a cytoplasm and what does it do?

A

It is a liquid gel in which the organelles are suspended and where most of the chemical reactions need for life take place.

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9
Q

What is a cell membrane and what does it do?

A

It lies on the outside of a cell and it controls the passage of substances such as glucose and mineral ions into the cell. It also controls the movement of substances such as urea or hormones out of the cell.

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10
Q

What is mitochondria and what does it do?

A

It structures the cytoplasm where aerobic respiration takes place, releasing energy for the cell. They are very small: 1-2 um in length and only about 0.2-0.7 um in diameter.

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11
Q

What are ribosomes and what do they do?

A

They are where protein synthesis takes place, making all the proteins needed in the cell.

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12
Q

How do plants make their food ?

A

By photosynthesis

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13
Q

TRUE or FALSE…

Plant cells have all the features of an animal cell

A

TRUE

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14
Q

What are chloroplasts and what do they do?

A

Chloroplasts are found in all the green parts of a plant. They are green because they contain the green substance chlorophyll. Chlorophyll absorbs light so the plant can make food for photosynthesis. Each chloroplast is around 3-5um long. Root cells do not have chloroplasts because they are underground and do not photosynthesise.

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15
Q

What is a permanent vacuole and what does it do?

A

It is a space in the cytoplasm filled with cell sap. This is important for keeping the cells rigid to support the plant.

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16
Q

What cell parts do eukaryotic cells have?

A

They have a cell membrane, cytoplasm, genetic material that is enclosed in a nucleus and mitochondria.

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17
Q

What is genetic material?

A

It is a chemical called DNA and this forms structures chromosomes that are contained within the nucleus.

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18
Q

TRUE OR FALSE…

All animals including human beings, fungi, plants, and protista are eukaryotes.

A

TRUE

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19
Q

What cell parts do prokaryotic cells have? (give an example of a prokaryote)

A

Bacteria are single-celled living organisms. They are examples of prokaryotes. They are around 0.2-2.0 um in length.

Bacteria have a cytoplasm and a cell membrane surrounded by a cell wall, but the cell wall does not contain the cellulose you see in plant cells.

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20
Q

TRUE OR FALSE…

In prokaryotic cells, the genetic material is enclosed in a nucleus

A

FALSE

The bacterial chromosome is a single DNA loop found free in the cytoplasm.

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21
Q

What are plasmids, where are they found and what do they do?

A

Plasmids are found in some prokaryotic cells. They are an extra small ring of DNA. They code for very specific features such as antibiotic resistance.

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22
Q

What is a slime capsule, and where is it found?

A

Some bacteria have a protective slime capsule around the outside of the cell wall.

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23
Q

What are flagella, where is it found, and how can it be used?

A

Some type of bacterium has at least one flagellum (plural: flagella), that is, a long protein strand that lashes about and can help the bacterium move.

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24
Q

How do bacteria use their flagella?

A

The flagella are used to move the bacteria cell around.

25
Q

TRUE OR FALSE…

All bacteria have a bad impact on other organisms.

A

FALSE

Many bacteria have little or no effect on other organisms and many are very useful.

26
Q

What are the bad impacts of bacteria on the human body and our body contents?

A

Bacteria can cause diseases in humans and other animals also in plants. They can also decompose and destroy stored food.

27
Q

What is the difference in the differentiation of cells between plant and animal cells?

A

Most types of animal cells differentiate at an early stage of development, whereas many types of plant cells retain the ability to differentiate throughout life.

28
Q

What are nerve cells specialized to do?

A

Nerve cells are specialized to carry electrical impulses around the body of an animal. They provide a rapid communication system between different parts of the body.

29
Q

What adaptations does a nerve cell to be more effective?

A

Lots of dendrites to make connections to other nerve cells.

An axon that carries the nerve impulse from one place to another. They can be very long- the axon in a blue whale can be up to 25m long! The longest axon in your body runs from the base of your spine to your big toe.

The nerve endings or synapses are adapted to pass the impulses to another cell or between a nerve cell and a muscle in your body using special transmitter chemicals.

30
Q

What are muscle cells specialized to do?

A

Muscle cells are specialised cells that can contract and relax. Striated (striped) muscle cells work together in tissues called muscles. Muscles contract and relax in pairs to move the bones of the skeleton, so vertebrae can move on land and in water, and in some cases fly. Smooth muscle cells from one of the layers of tissue in your digestive system and they contract to squeeze food through your gut.

31
Q

What adaptations does a muscle cell to be more effective?

A

They contain special proteins that slide over one another making the fibres contract.

They contain mitochondria to transfer the energy needed for the chemical reactions that take place as the cells contract and relax.

They can store glycogen, a chemical that can be broken down and used in cellular respiration by the mitochondria to transfer the energy needed for the fibres to contract.

32
Q

What are sperm cells specialized to do?

A

Sperm cells are specialised to bine with the egg cell of a female for fertilisation Sperm cells are usually released a long way from they are going to fertiilse. They contain the genetic information from the male parent. Depending on the type of animal, sperm cells need to move through water or the female reproductive system to reach the egg. They then have to break into the egg.

33
Q

What adaptations does a sperm cell to be more effective?

A

A long tail whips from side to side to help move the sperm through water or the female reproductive system.

The middle section is full of mitochondria, which transfer the energy needed for the tail to work.

The acrosome stores digestive enzymes for breaking down the outer layers of the egg.

A large nucleus contains the genetic information to be passed on.

34
Q

Define the term resolution

A

Resolution is the ability to distinguish between two separate points in an image

35
Q

Define the word ‘magnification’

A

Magnification is how much bigger an image is compared to its actual size. Can be calculated by using the IAM triangle.

36
Q

Define diffusion.

A

Diffusion is the net random movement of particles from an area of high concentration to an area of low concentration.

37
Q

Define Osmosis

A

Osmosis is the net random movement of WATER from an area of high concentration to an area of low concentration, across a PARTIALLY PERMEABLE MEMBRANE.

38
Q

What is meant by a passive process?

A

A passive process does not require ATP energy.

39
Q

What is meant by an active process?

A

An active process requires ATP energy from respiration.

40
Q

What happens to an animal cell when it is placed in a more DILUTE solution?

A

The cell gains water by osmosis and may burst. This is called lysis.

41
Q

What happens to an animal cell when it is placed in a more CONCENTRATED solution?

A

The cell loses water by osmosis shrivels. This is called crenation.

42
Q

Define active transport

A

The movement of substances from an area of LOW concentration to an area of HIGH concentration across a PARTIALLY PERMEABLE MEMBRANE.

ATP energy is needed and a carrier protein in the membrane.

43
Q

What happens to a plant cell when it is placed in a more DILUTE solution?

A

The cell gains water by osmosis but does not burst.

This cell is now turgid.

44
Q

Why does a plant cell not burst when it is placed in a more dilute solution?

A

The plant cell has a cell wall.

45
Q

What happens to a plant cell when it is placed in a more CONCENTRATED solution?

A

The cell loses water by osmosis. The cell membrane pulls away from the cell wall. This is called plasmolysis.

46
Q

Give an example of molecules that move by active transport.

A

Mineral ions in the soil are in low concentration. They enter the root hair cells via active transport.

47
Q

Where does ATP energy come from?

A

It is released during aerobic respiration in the mitochondria.

48
Q

How do you calculate % change in mass?

A

(Final mass - initial mass) ÷ (initial mass) x 100

49
Q

Which type of cells do NOT have a nucleus?

A

Prokaryotic cells

50
Q

How are root hair cells adapted for their function?

A

● Have a large surface area due to root hairs, meaning more water can be absorbed by osmosis.

● The large permanent vacuole affects the speed of movement of water from the soil to the cell.

● Have mitochondria to provide energy from respiration for the active transport of mineral ions into the root hair cell.

51
Q

How are xylem cells adapted for their function?

A

● Xylem cells hollow and are joined end-to-end to form a continuous tube so water and mineral ions can move through.

● Lignin is deposited in spirals which helps the cell walls which helps withstand the pressure from the movement of water.

52
Q

How are phloem cells adapted for their function?

A

● Cell walls of each cell form structures called sieve plates when they break down, allowing the movement of substances from cell to cell.

● Have few organelles so food can move faster.

● Have a companion cell with mitochondria to supply energy.

53
Q

What is the function of root hair cells in a plant?

A

They are specialized to absorb water by osmosis and mineral ions by active transport from the soil.

54
Q

What is the function of xylem cells in a plant?

A

They are specialised to transport water and mineral ions up the plant from the roots to the shoots.

55
Q

What is the function of phloem cells in a plant?

A

Transports food (by translocation) from the leaves to other parts of the plant.

56
Q

How do you convert mm to μm?

A

x1000

57
Q

Convert 35mm into μm

A

35mm x 1000 = 35,000μm

58
Q

Convert 4.7mm in μm

A

4.7mm x 1000 = 4,700μm

Biology (8 decks)

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