Combined Biology - 4.1 Flashcards Preview

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Flashcards in Combined Biology - 4.1 Deck (52)
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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.