B1-Cell Biology

Question 1

Are eukaryotic cells complex or simple and are they plant/animal or bacteria cells?

Answer 1

Complex
Plant and animal

Question 2

Are prokaryotic cells complex or simple and are they plant/animal or bacteria cells?

Answer 2

Smaller and simpler
Bacteria cells mostly (any single-celled organism)

Question 3

Eukaryotes are organisms made up of…

Answer 3

eukaryotic cells

Question 4

Prokaryote is an organism made up of…

Answer 4

a prokaryotic cell (it’s a single-celled organism)

Question 5

What subcellular structures do most animal cells have?

Answer 5

-Nucleus
-Cytoplasm
-Cell membrane
-Mitochondria
-Ribosomes

Question 6

What is the function of a nucleus?

Answer 6

Contains genetic material that controls the activities of the cell

Question 7

What is the function of the cytoplasm?

Answer 7

Gel-like substance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions.

Question 8

What is the function of cell membrane?

Answer 8

Holds the cell together and controls what goes in and out.

Question 9

What is the function of mitochondria?

Answer 9

These are where most of the reactions for aerobic respiration occur.

Question 10

What is the function of ribosomes?

Answer 10

Where proteins are synthesised in the cell.

Question 11

What extra subcellular structures do plant cells have compared to animal cells?

Answer 11

1)Rigid cell wall- made of cellulose.
2)Permanent vacuole-contains cell sap
3)Chloroplasts-contain chlorophyll

Question 12

What is the function of rigid cell wall?

Answer 12

It supports the cell and strengthens it.

Question 13

What is the function of permanent vacuole?

Answer 13

Contains cell sap- a weak solution of sugar and salts- to keep the cell turgid swollen and hard.

Question 14

What is the function of chloroplasts?

Answer 14

Where photosynthesis occurs, which makes food for the plant (glucose). They contain a green substance called chlorophyll, which absorbs the light needed for photosynthesis.

Question 15

What subcellular structures does a bacteria (prokaryote) cell have?

Answer 15

-Cell membrane
-Cytoplasm
-Cell wall
-Ribosomes
-Single circular strand of DNA that floats freely in the cytoplasm
-May also contain one or more small rings of DNA called plasmids.

Question 16

What subcellular structures doesn’t a bacteria (prokaryote) cell have?

Answer 16

-Mitochondria or chloroplasts
-Nucleus
-Vacuole

Question 17

How do LIGHT microscopes form an image and magnify it?

Answer 17

Through light and lenses.

Question 18

How do ELECTRON microscopes form an image?

Answer 18

They use electrons.

Question 19

What is the difference between a LIGHT microscope and an ELECTRON microscope?

Answer 19

-Electron microscope has a greater magnification and a higher resolution (subcellular structures can be distinguished more easily- gives a sharper image).
-This means electron microscopes allow us to see much smaller things in more detail.
-Specimen has to be dead when being viewed under electron, specimen can be alive when being viewed under light.

Question 20

What is the formula for magnification?

Answer 20

magnification= image size/real size

Image size and real size should have same units, if not then convert before putting into equation

Question 21

For preparing cells to be viewed under a microscope, you need to use:

Answer 21

-Tweezers
-Iodine SOLUTION (stain)
-Cover slip
-Slide

Question 22

The different parts of a microscope include:

Answer 22

-Eyepiece lens
-Coarse adjust knob (moves stage)
-Fine adjustment knob (adjust focus of lens)
-High and low power objective lenses
-Stage
-Light OR possibly a mirror with which a light is shone on it

Question 23

Define differentiation

Answer 23

The process by which a cell changes to become specialised for its job (e.g. red blood cell, white blood cell)

Question 24

Cells that differentiate in mature animals are mainly used for…

Answer 24

repairing and replacing cells, such as skin or blood cells

Question 25

What are undifferentiated cells known as?

Answer 25

Stem cells

Question 26

What examples of animal cells are specialised? Think about how they are adapted.

Answer 26

-Sperm cells for reproduction(long tail, streamlined head, lots of mitochondria, enzymes in its head for digesting the egg cell membrane)
-Nerve cells for rapid signalling (long to cover more distance, branched connections to connect to other nerve cells to form a network)
-Muscle cells for contraction (long so have space for contraction, lots of mitochondria releases energy for contraction)

Question 27

What examples of plant cells are specialised? Think about how they are adapted.

Answer 27

-Root hair cells for absorbing water/minerals (long “hairs” stick into soil increasing surface area for absorption)
-Phloem and xylem cells for transporting substances (the respective cells form phloem and xylem tubes which transport food and water around plant, to form tubes cells are joined end to end, xylem cells are hollow in centre and phloem cells have very few subcellular structures so stuff can flow)

Question 28

What are chromosomes and where are they found?

Answer 28

Coiled up lengths of DNA molecules in nucleus.

Question 29

How many chromosomes does a human cell contain?

Answer 29

46 chromosomes, 23 pairs

Question 30

What does the cell cycle produce?

Answer 30

New cells for growth, development and repair

Question 31

What is the stage called where the cell divides in the cell cycle?

Answer 31

Mitosis

Question 32

What is the result at the end of the cell cycle?

Answer 32

Two new daughter cells genetically identical to the parent cell, with the same number of chromosomes/same DNA. The two new daughter cells are genetically identical to each other and to the parent cell.

Question 33

What’s the equation to calculate the number of times a bacterial cell has divided in a certain amount of time, so the number of cells it has produced in that time?

Answer 33

Total time (bacteria are growing)/mean division time (ensure they are both in same units i.e. minutes)
Do 2 to the power of how many divisions to find the total number of bacterial cells produced.
Put answer in units of ‘cells’

Question 34

What do you have to ensure you do when creating an investigation for comparing zones of inhibition on agar plates?

Answer 34

Not to take the lid off of the petri dish when measuring diameter of zone of inhibition. Should be visible through bottom of petri dish.

Question 35

How do you calc the area of an inhibition zone (what equation)?

Answer 35

Area= πr^2

Question 36

How do you find the area of a bacteria colony in an agar plate?

Answer 36

Measure diameter of colony then use: Area=πr^2

Question 37

Why is therapeutic cloning used (in terms of stem cells)?

Answer 37

A type of cloning that allows for an embryo to have the same genetic information as patient=stem cells produced from said embryo contain same genes as patient so won’t be rejected by patient’s body.

Question 38

Where are stem cells found in plants?

Answer 38

In meristems (parts of plant where growth occurs).

Question 39

Can plant cells found in meristem tissues always differentiate throughout their entire life?

Answer 39

Yes, they can differentiate into any type of cell.

Question 40

What is the purpose of plant stem cells?

Answer 40

-To produce clones (genetically identical copies) of whole plants quickly and cheaply.
-Be used to grow more plants of rare species (to prevent being wiped out).
-Can be used to grow crops of identical plants that have desired features from farmers, e.g. disease resistance (not immunity due to no immune system)