Topic 1 - Cell Biology

Question 1

What is a prokaryotic cell?

Answer 1

bacterial cells

Question 2

What is a eukaryotic cell?

Answer 2

animal and plant cells

Question 3

What are the 5 animal subcellular structures?

Answer 3

Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes

Question 4

What are the 8 plant subcellular structures?

Answer 4

Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes + cell wall, permanent vacuole, chloroplasts

Question 5

What is the role of the nucleus?

Answer 5

it contains genetic material that controls the activities of the cell

Question 6

What is the role of cytoplasm?

Answer 6

this is where most of the chemical reactions happen which are controlled by enzymes

Question 7

What is the role of the cell membrane?

Answer 7

holds the cell together and controls what goes in and out

Question 8

What is the role of mitochondria?

Answer 8

where aerobic respiration transfers energy that the cell needs to work

Question 9

What is the role of ribosomes?

Answer 9

where protein is made

Question 10

What is the role of the cell wall?

Answer 10

supports the cell and strengthens it

Question 11

What is the role of the permanent vacuole?

Answer 11

it contain cell sap, a weak solution of sugar and salts

Question 12

What is the role of chloroplasts?

Answer 12

where photosynthesis occurs which makes food for the plant

Question 13

Which is smaller, prokaryotes or eukaryotes?

Answer 13

prokaryotes

Question 14

What do light microscopes do?

Answer 14

they use light and lenses to form an image of a specimen and magnify it

Question 15

How does an electron microscope work?

Answer 15

it uses a beam of electrons which are focused using magnets. the electrons hit a fluorescent screen which emits visible light, producing an image.

Question 16

What is the difference between light and electron microscopes?

Answer 16

Electron microscopes have a much higher resolution than light microscopes and let us see smaller things in more detail

Question 17

What is the formula for magnification?

Answer 17

magnification = image size/real size

Question 18

What is cell differentiation?

Answer 18

differentiation is the process by which a cell changes to become specialised for its job.

Question 19

What are the differences between eukaryotic and prokaryotic cells?

Answer 19

prokaryotic cells are much smaller than eukaryotic cells. eukaryotic cells contain membrane bound-organelles and a nucleus containing genetic material, while prokaryotes do not.

Question 20

What are plasmids?

Answer 20

small circular loops of DNA found free in the cytoplasm and separate from the main DNA.

Question 21

How are sperm cells in animals adapted to their functions?

Answer 21

tail - enables movement
mitochondria - provide energy for tail movement
haploid nucleus - contains genetic information.

Question 22

How are nerve cells in animals adapted to their functions?

Answer 22

long axon - allows electrical impulses to be transmitted all over the body from the central nervous system
dendrites - from the cell body connect to and receive impulses from other nerve cells, muscles and glands

Question 23

How are muscle cells in animals adapted to their functions?

Answer 23

arrangement of protein filaments - allows them to slide over each other to produce muscle contraction
mitochondria - to provide energy for muscle contraction

Question 24

How are root hair cells in plants adapted to their functions?

Answer 24

large surface area - to absorb nutrients and water from surrounding soil
thin walls - do not restrict water absorption

Question 25

How are xylem cells in plants adapted to their functions?

Answer 25

no upper or lower margins between cells - to provide a continuous route for the water to flow thick woody side walls - strengthen their structure and prevent collapse

Question 26

How are phloem cells in plants adapted to their functions?

Answer 26

sieve plates - let dissolved amino acids and sugars be transported up and down the stem companion cells - provide energy needed for active transport of substances along the phloem

Question 27

Why is cell differentiation important?

Answer 27

allows production of different tissues and organs that perform various vital functions in the human body

Question 28

At what point in their life cycle do most animal cells differentiate?

Answer 28

early in their life cycle

Question 29

For how long do plant cells retain the ability to differentiate?

Answer 29

throughout their entire life cycle

Question 30

What is the purpose of cell division in mature animals?

Answer 30

repair and replacement of cells

Question 31

What changes does a cell go through as it differentiates?

Answer 31

becomes specialised through acquisition of different sub-cellular structures to enable a specific function to be performed by the cell

Question 32

What is magnification?

Answer 32

the number of times bigger an image appears compared to the size of the real object

Question 33

What is resolution?

Answer 33

the smallest distance between two objects that can be distinguished

Question 34

What are the advantages of light microscopes?

Answer 34

- inexpensive - easy to use - portable - observe both dead and living specimens

Question 35

What is the disadvantage of light microscopes?

Answer 35

limited resolution

Question 36

What are the two types of electron microscopes?

Answer 36

transmission electron microscope (TEM) | scanning electron microscope (SEM)

Question 37

What are the advantages of electron microscopes?

Answer 37

- greater magnification | - greater resolution

Question 38

Why do electron microscopes have a greater magnification and resolution?

Answer 38

they use a beam of electrons which has a shorter wavelength than photons of light.

Question 39

What are the disadvantages of electron microscopes?

Answer 39

- expensive - large so less portable - require training to use - only dead specimens can be observed

Question 40

How do bacteria multiply?

Answer 40

binary fission (simple cell division)

Question 41

How often do bacteria multiply?

Answer 41

once every 20 minutes if enough nutrients are available and the temperature is suitable

Question 42

What are two ways bacteria can be grown?

Answer 42

- nutrient broth solution | - colonies on an agar gel plate

Question 43

What nutrients make up a nutrient broth solution?

Answer 43

all nutrients required for bacteria to grow including nitrogen for protein synthesis, carbohydrates for energy and other minerals.

Question 44

What are uncontaminated cultures of microorganisms needed for?

Answer 44

investigating disinfectant and antibiotic action