Cell biology

Question 1

What is a Eukaryotic cell?

Answer 1

A Eukaryotic cell is a cell with a nucleus such as a plant or animal cell

Question 2

What does a cell membrane do?

Answer 2

Cell membrane controls the movement of substances in and out of the cell

Question 3

What is cytoplasm?

Answer 3

Cytoplasm is a jelly like substance where reactions take place

Question 4

Where does respiration take place?

Answer 4

Respiration takes place in the mitochondria

Question 5

Where are proteins made?

Answer 5

Proteins are made in the ribosomes

Question 6

What type of cell contains no nucleus?

Answer 6

A prokaryotic cell, such as a bacteria cell, contains cytoplasm and a cell membrane but no nucleus

Question 6

What is differentiation?

Answer 6

Differentiation is when a cell becomes specialised by developing different sub cellular structures to enable it to carry out different functions

Question 6

What are cell walls made of and what is its purpose?

Answer 6

Cell walls are made up of cellulose and give the cell structure

Question 6

What do chloroplasts do?

Answer 6

Chloroplasts contain chlorophyll which is used to absorb sunlight for photosynthesis

Question 6

What does a vacuole store and what is its purpose?

Answer 6

The vacuole stores cell sap and gives the cell structure

Question 7

What does a nucleus store?

Answer 7

The nucleus contains chromosomes which store genetic material

Question 8

Give one plant and one animal cell example of how cells can differentiate

Answer 8

Animal - Sperm cell: has many mitochondria to release more energy for swimming

Plant - Mesophyll: has many chloroplasts for photosynthesis

Question 9

When do plant and animal cells differentiate?

Answer 9

Animal cells differentiate at an early stage of life

Plant cells can differentiate throughout their life

Question 10

How do you work out magnification?

Answer 10

Magnification = image size / actual size

Question 11

what does a micrometre and a nanometre symbol look like?

Answer 11

μm = micrometre nm = nanometre

Question 12

How much is 1 mm in μm?

Answer 12

1mm = 1000 μm

Question 13

Was the light microscope or electron microscope developed first?

Answer 13

The light microscope was first developed

Question 14

Which microscope has the better resolution and magnification?

Answer 14

The electron microscope gives a higher resolution and magnification which allows us to see subcellular structures in more detail

Question 15

What does Mitosis allow cells to do?

Answer 15

Mitosis allows cells to divide for growth, repair and development of an embryo

Question 16

What are the 3 stages of mitosis?

Answer 16

Stage 1 – DNA is copied & number of subcellular structures, mitochondria & ribosomes are increased
Stage 2 – chromosomes are pulled to either end of the cell and nucleus divides
Stage 3 – cytoplasm and cell membranes divide to form 2 genetically identical cells

Question 17

What are stem cells?

Answer 17

Stem cells are undifferentiated cells found in embryos, adult animals and meristems in plants

Question 18

What can stem cells be used for?

Answer 18

Stem cells from human embryos can be cloned and made to differentiate into most different types of human cells. This can be used to help illnesses such as diabetes and paralysis

Question 19

What are the risks of stem cells?

Answer 19

Use of stem cells has risks, such as transfer of viral infection and religious and ethical objections about killing a potential human life

Question 20

What can stem cells in plants be used for?

Answer 20

Stem cells in plants can be used to produce clones of plants quickly and economically

Question 21

What is diffusion?

Answer 21

Diffusion is the passive movement of particles from a high concentration to a low concentration

Question 22

What can affect rate of diffusion?

Answer 22

Rate of diffusion can be changed by altering concentration gradient, temperature and surface area

Question 23

What are surfaces and organs in multicellular organisms specialised for?

Answer 23

For multicellular organisms, surfaces and organ systems are specialised for exchanging materials

Question 24

How can the effectiveness of an exchange material be altered?

Answer 24

The effectiveness of an exchange surface is increased by – i. Having a large surface area ii. Thin membrane iii. Efficient blood supply (in animals) iv. Being ventilated (in animals for gas exchange)

Question 25

What is osmosis?

Answer 25

Osmosis is the passive movement of water from an area of higher water concentration to an area of lower water concentration, across a partially permeable membrane

Question 26

What are mass changes caused by?

Answer 26

Mass changes are caused by the movement of water across a plant cell membrane

Question 27

What is active transport?

Answer 27

Active transport uses energy from respiration, to transport substances across a membrane from low concentration to high concentration

Question 28

Where is active transport used?

Answer 28

Active transport is used in root hair cells and the small intestine for the absorption of nutrients