Separate Biology - B1 Cell Biology Flashcards Preview

Separate Science - Biology Paper 1 > Separate Biology - B1 Cell Biology > Flashcards

Flashcards in Separate Biology - B1 Cell Biology Deck (63)
Loading flashcards...
1
Q

Are animal and plant cells eukaryotic or prokaryotic?

A

Eukaryotic

2
Q

Are bacterial cells eukaryotic or prokaryotic?

A

Prokaryotic

3
Q

Q. What type of cell is shown in the diagram below?

Q. What key feature allows you to identify the cell below?

Q. Name the different parts of the cell.

A
  • Bacterial cell
  • The genetic material is not enclosed in a nucleus.
4
Q

Name the different parts of the animal cell below

A
5
Q

Name the different parts of the plant cell below.

A
6
Q

Which cells are the smallest out of bacterial cells, animal cells and plant cells?

A

Bacterial cells

7
Q

Match the following prefixes to the corresponding standard form.

A
8
Q

Q. What is a plasmid?

Q. In which type of cells are plasmids found?

A
  • A plasmid is a ring of DNA
  • Plasmids are found in bacterial cells
9
Q

Give the functions of the following cell parts:

a) Ribosomes
b) Mitochondria
c) Cell membrane
d) Nucleus

A

a) Ribosomes: Protein synthesis
b) Mitochondria: Where respiration happens
c) Cell membrane: Controls what goes in and out of the cell
d) Nucleus: Controls cells activity (where DNA is kept)

10
Q

Q. Give the functions of the following cell parts:

a) Cell wall
b) Vacuole
c) Chloroplasts
d) Cytoplasm

A

a) Cell wall: Strengthens the cell
b) Vacuole: Contains cell sap (water, salts and sugars)
c) Chloroplasts: Where photosynthesis happens
d) Cytoplasm: Where chemical reactions occur

11
Q

What is the main molecule that makes up cell walls?

A

Cellulose

12
Q

Name three cell parts that are found in plant cells but not found in animal cells.

A
  • Cell wall
  • Chloroplasts
  • Vacuole
13
Q

How would you use the scale to estimate the size of the cell indicated by the arrow?

A
  • Measure the width of the cell using a ruler, call this ‘a’.
  • Measure the width of the scale using a ruler, call this ‘b’
  • Divide ’a’ by ‘b’ then multiply the answer by the scale value (in this case 0.1 mm)
14
Q

Name the following specialised animal cells and explain how they are adapted for their particular function.

A

a) Sperm cell: Long tail and streamline to help swim to the egg. Lots of mitochondria for energy. Enzymes in head to help digest into egg.
b) Nerve cell: Long with branched connections to form a network with other nerve cell.
c) Muscle cell: Long and contain lots of mitochondria to release energy for contraction.

15
Q

Name the following specialised plant cells and explain how they are adapted for their particular function.

A

a) Root hair cell: Large surface area for absorbing water and minerals. Note: no chloroplasts as unable to photosynthesise under ground.
b) Xylem cell: Hollow cells that allow water and mineral ions to be transported.
c) Phloem cell: Not hollow, but have few sub-cellular parts to allow substances to flow through them

16
Q

What is ‘differentiation’ ?

A

The process by which a cell becomes specialised

17
Q

Animal cells differentiate at any early stage. How is this different to plant cells?

A

Many types of plant cells retain the ability to differentiate throughout life.

18
Q

In mature animals, what is the main purpose of cell division?

A

For repair and replacement of cells

19
Q

Q. Why is an electron microscope better than a light microscope?

Q. Why have electron microscopes been useful for understanding cell structure?

A
  • Better magnification, better resolution.
  • Cells can be seen in much finer detail, therefore scientists now know more about sub-cellular structures.
20
Q

What equation links magnification, size of image and size of real object.

A

magnification=(size of image)/(size of real object)

21
Q

The development of what piece of equipment has led to a better understanding of sub-cellular parts?

A

Electron microscope

22
Q

Describe the stages of mitosis

A
  • Cell grows and increases number of sub-cellular structures (e.g. ribosomes and mitochondria)
  • DNA replicates to form two copies of each chromosome.
  • One set of chromosome is pulled to each end of the cell and the nucleus divides.
  • The cytoplasm and cell membranes divide to form two identical cells.
23
Q

Why is cell division by mitosis important?

A

For growth and development

24
Q

How is the DNA arranged within a nucleus?

A

Within chromosomes

25
Q

What is a stem cell?

A

An undifferentiated cell that is capable of becoming a variety of other cells.

26
Q

What are the two main places where human stem cells are found?

A
  • Embryos
  • Adult bone marrow
27
Q

Why are embryonic stem cells more useful than stem cells from adult bone marrow?

A

Embryonic stem cells are able to differentiate into a greater variety of cells.

28
Q

Which type of stem cells are used to make blood cells and many other types of cells in an adult human.

A

Stem cells from bone marrow

29
Q

Where are stem cells found in plants?

A

In the meristem tissue

30
Q

Name two conditions that stem cells can be used to treat.

A
  • Diabetes
  • Paralysis
31
Q

Q. What is therapeutic cloning?

Q. What is the main advantage of therapeutic cloning?

A
  • An embryo is produced containing same genes as patient. These stem cells are used to make cells or tissues to treat the patient.
  • These stem cells are not rejected by the patient’s body.
32
Q

Give two reasons why someone might want to use plant stem cells to produce clones of plants.

A
  • Rare species can be cloned to protect from extinction.
  • Crop plants with special features (e.g. disease resistance) can be cloned to produce large numbers of identical plants for farmers.
33
Q

By what process to substances move in and out of cells along a concentration gradient?

A

Diffusion

34
Q

What is diffusion?

A

The spreading out of particles from an area of high concentration to an area of low concentration.

35
Q

Give two examples of where diffusion takes place in the body.

A

Examples include:

  • Diffusion of oxygen from lungs into blood
  • Diffusion of carbon dioxide from blood plasma into lungs
  • Diffusion of urea from cells into the blood plasma
  • Diffusion of nutrients from villi (in small intestine) into blood.
36
Q

Name three factors that affect the rate of diffusion.

A
  • Concentration gradient (difference in concentrations)
  • Temperature
  • Surface area of the membrane
37
Q

Calculate the surface area to volume ratio of the following objects:

*these are examples only, you will need to be able to this for any given object

A

Large box:

SA:Vol = 8:3

Small box:

SA:Vol = 16:3

38
Q

What two things increase the effectiveness of an exchange surface in plants?

A
  • Large surface area
  • Thin membrane
39
Q

Do single-celled organisms have a relatively small or large surface area to volume ratio?

A

• Large surface area to volume ratio

40
Q

Explain how the alveoli in the lungs are adapted for gas exchange.

A
  • Large surface area
  • Thin membrane
  • Close to efficient blood supply
  • Moist lining
  • Ventilated (air moves in and out)
41
Q

Why do multicellular organisms need exchange surfaces?

A

They have a relatively small surface area to volume ratio so need exchange surfaces to increase the surface area for diffusion of substances.

42
Q

Describe how fish gills are adapted for exchanging oxygen and carbon dioxide.

A
  • Gill filaments create a large surface area
  • Gill filaments have lamellae which increase surface area more.
  • Lamellae have lots of blood capillaries
  • Thin surface layer
  • Large concentration gradient maintained
43
Q

Describe how small intestine is adapted for exchanging materials.

A
  • Covered in millions of villi
  • Villi provide a large surface area
  • Villi have a single layer of surface cells
  • Close network of capillaries
44
Q

Describe how the plant root is adapted for exchanging materials.

A
  • Root covered in millions of tiny hairs
  • Root hair cells have a large surface area
  • Root hair cells have a thin surface
45
Q

Describe how the leaf is adapted for exchanging materials.

A
  • Leaves are flat to increase the surface area
  • Tiny holes (stomata) allows gases to diffuse in and out.
  • Air spaces in leaf expose more surface of the cells
46
Q

By what process does water move across cell membranes?

A

Osmosis

47
Q

What is osmosis?

A

The diffusion of water from a dilute solution (where there are more water particles) to a concentrated solution (where there are less water particles) through a partially permeable membrane.

48
Q

Use the data from the table to calculate the percentage change in mass of the potato.

*this is an example only. You need to be able to do this for any given data for any situation.

A

Working out

1: % change=((7.5-5.0)/5.0) x 100
2: % change=((7.5-10.0)/10.0) x 100

49
Q

What is Active Transport?

A

The movement of substances from a lower concentration (more dilute) to a higher concentration (more concentrated)

50
Q

Where does the energy for Active Transport come from?

A

Respiration

51
Q

Give an example of active transport in plant roots.

A

Mineral ions move from the soil into plant root hairs by active transport.

52
Q

Describe how molecules can move by active transport in the blood.

A

Digested food molecules (e.g. sugar) can move from lower concentrations in the gut to higher concentrations in the blood.

53
Q

Separate Q. What is the name for the cell division of prokaryotic cells such as bacteria?

A

Binary fission

54
Q

Separate Q. How frequently can some bacteria multiply if they are given enough nutrients and optimum temperature?

A

Up to once every 20 minutes

55
Q

Separate Q. What are the two ways in which bacteria can be grown in a lab?

A
  • In nutrient broth
  • On agar plates
56
Q

Separate Q. Why might a scientist want to grow an uncontaminated culture of bacteria?

A

To investigate the effectiveness of disinfectants on bacteria.

57
Q

Separate Q. Describe how you prepare an uncontaminated culture of bacteria using an aseptic technique.

A
  1. Sterilise the petri dish and culture media
  2. Pass the inoculating loop through a flame
  3. Dip inoculating loop in bacterial culture and spread evenly over agar jelly
  4. Secure the lid of the petri dish with tape
  5. Store the petri dish upside down at 25 oC
58
Q

Separate Q. Explain why you do each of the following stages when preparing an uncontaminated culture of bacteria:

  1. Sterilise the petri dish and culture media
  2. Pass the inoculating loop through a flame
  3. Secure the lid of the petri dish with tape
  4. Store the petri dish upside down
A
  1. To kill any unwanted microorganisms
  2. To kill any unwanted microorganisms
  3. To stop microorganisms from air getting in
  4. To stop drops of condensation falling onto agar surface.
59
Q

Separate Q. What is the maximum temperature that bacterial cultures should be kept at in school and college laboratories? And why?

A
  • 25 oC
  • No higher because harmful pathogens are more likely to grow above this temperature.
60
Q

Separate Q. Describe how you would set up an agar plate to test the effectiveness of two different antibiotics.

A
  • Evenly spread bacteria over a petri dish (using aseptic technique)
  • Place antibiotic disks on agar jelly so they are not touching.
  • Secure lid with tape and incubate at 25 oC
  • Measure the inhibition zone (where no bacteria is present).
  • The bigger the inhibition zone, the more effective the antibiotic.
61
Q

Separate Q. Calculate the area of the inhibition zone in the diagram

A

Diameter = 2 cm

Radius = 1 cm

Use A=πr2 to find area of inhibition zone.

A=π x 12

A = 3.14 cm2

62
Q

Separate Q. Describe what happens in the process of binary fission.

A
  • DNA and plasmids replicate
  • Cell gets bigger and DNA moves to opposite ends of cell
  • Cytoplasm divides and new cell walls form
  • Two daughter cells are produced – each cell has an identical copy of DNA but the number of plasmids they contain may vary
63
Q

Separate Q. If a bacterial cell has a mean division time of 30 minutes, how many cells will it have produced after 2 hours?

*this is just an example, you will have to be able to do this calculation when given appropriate information about mean division time.

A

16 bacterial cells

Working out: Number of bacteria after time = 2X (where ‘X’ = number of cell divisions).

Number of cell divisions = total time / mean division time

*make sure total time and mean division time have the same units. (i.e. both minutes or both hours)