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Biology with NAJI the legend > Cell Biology > Flashcards

Cell Biology Flashcards

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1
Q

In general what are the two types of cells?

A

1) Eukaryotic - true nucleus

2) Prokaryotic - no nucleus

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2
Q

What are some examples of Eukaryotic cells?

A

1) Animal cells

2) Plant cells

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3
Q

What are some examples of Prokaryotic cells?

A

1) Bacteria

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4
Q

What are the different components of an animal cell?

A

(From outside to in)

> Cell membrane 
> Cytoplasm 
> Mitochondria 
> Nucleus 
> Ribosomes
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5
Q

What are the different components of a plant cell?

A

(From outside to in)

> Cell wall 
> Cell membrane 
> Cytoplasm 
> Choloroplasts 
> Mitochondria 
> Ribosomes 
> Vacuole 
> Nucleus
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6
Q

What is the function of the nucleus?

A

> Store genetic material (DNA, RNA ) - this genetic material helps to control cell activity.
Site of DNA replication and synthesis.

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7
Q

What is the cytoplasm?

A

> Gel like substance that provides a platform for other organelles e.g. mitochondria and ribosomes.

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8
Q

What is the function of the mitochondria?

A

> Powerhouse of the cell

> Site of aerobic respiration (remember that anaerobic respiration happens in the cytoplasm!!!).

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9
Q

What is the function of a ribosome?

A

> Carries out protein synthesis

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10
Q

What is the function of a cell membrane?

A

> Controls substances that enter/leave the cell.

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11
Q

What is the function of a chloroplast?

A

> Stores green pigment (chlorophyll) which absorbs light for photosynthesis to occur.

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12
Q

What is the cell wall?

A

> Rigid structure that helps to strengthen and support the plant cell.

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13
Q

What is the cell wall made out of?

A

> Cellulose (carbohydrate that we cant digest).

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14
Q

What is the vacuole?

A

> Sap that stores water and minerals for the plant to use.

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15
Q

What does a bacterial cell look like?

A

From outside to inside view

> Cell wall 
> Cell membrane 
> Cytoplasm 
> Genetic material floating about 
==> Large singular DNA strand 
==> Plasmids (ring shaped).
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16
Q

What organelles do bacterial cells not have?

A

> Chloroplasts

>Mitochondria

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17
Q

What are the different types of microscopes?

A

> Light microscope ==> uses light and lenses to magnify an image.
Electron microscope ==> uses electrons to magnify an image.

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18
Q

Which type of microscope has a better resolution?

A

> Electron microscope ==> they have greater resolution than light microscopes.

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19
Q

What equation do you use to find the magnification of an organelle within a cell?

A

Magnification = image size/real size

image = size under the microscope
real size = what it actually is.

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20
Q

How do we go from 1m to 1mm?

A

divide by 1000

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21
Q

How do we go from 1mm to 1 micrometre?

A

divide by 1000

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22
Q

How do we go from 1m to 1 micrometre?

A

divide by 1 million (1,000,000)

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23
Q

How do you prepare a slide for organic material (e.g. onion skin)?

A

1) Add a drop of water into the middle of the clean slide.
2) Cut up an onion and separate it into layers. Use tweezers to peel off the epidermal (surface) tissue from the bottom of one of the layers.
3) Using the tweezers, place the epidermal tissue on the water on the slide.
4) Add a drop of iodine solution to test for starch. The presence of starch will be indicated by a blue-black colouration.
5) Place the cover -slip onto the slide. Then place the slide under the microscope. Look down the microscope via the eye-piece to view the specimen.

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24
Q

What are the components of a light microscope?

A

From up to down:

> Eye piece
> High and low power objective lenses 
> Stage (containing the slide and coverslip). 
> Coarse adjusting knob 
> Fine adjusting knob
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25
Q

What is the difference between the coarse adjusting knob and the fine adjusting knob?

A

> Fine adjusting knob ==> Focus image

> Coarse adjusting knob ==> Move the stage up and down

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26
Q

What is the difference between cells, tissues and organs?

A

Tissues are a group of similar cells.

Organs are a group of different tissues.

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27
Q

What cell forms when a sperm cell fuses with an egg cell?

A

Zygote

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28
Q

Is zygote a specialised or unspecialised cell?

A

Unspecialised ==> because it has the ability to turn into any type of cell.

Embryonic stem cells are cells that derive from the zygote.
Adult stem cells are cells derived from the bone marrow.
Stem cells are unspecialised cells.

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29
Q

What are examples of specialised cells in animals?

A 
> Red blood cells 
> Liver cells 
> Hair cells
> Sperm cells / Ovum (Reproductive cells).
> Nerve cells 
> Muscle cells
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30
Q

What is meant by differentiation?

A

It is the process by which cells change in a way to carry out a specific function. It is the process by which the cell becomes specialised.

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31
Q

What are examples of specialised cells in plants?

A

> Root hair cells
Xylem cells (transports water)
Phloem cells (transports food).

32
Q

What are sperm cells specialised to do?

A

> To carry male DNA for purposes of fertilisation.

33
Q

How are sperm cells specialised to do its job?

A

> Streamlined head
Motile tail that can propel the sperm towards the egg.
Mitochondria to provide energy for movement to occur.
Digestive enzymes in its head to break down the egg cell membrane.

34
Q

What are the functions of nerve cells?

A

> To transmit electrical signals to and from the brain.

35
Q

How are nerve cells specialised to do their job?

A

> Nerve cells have dendrites, cell body (soma) and axons.
Dendrites are very branched - this increases their surface area to receive messages.
Axons are covered with myelin to increase their rate of electrical conductance.
Nerve cells connect with each other via synapses. Here, neurotransmitters are released from axon terminals and diffuse across the synapse. They then bind to receptors found on the surface of the postsynaptic neuron. This helps to trigger an action potential (electrical activity) within the postsynaptic neuron. Hence, electrical message is passed to the postsynaptic neuron.

36
Q

What is the function of a muscle cell?

A

To contract and therefore enable movement to occur.

37
Q

How are muscle cells specialised for their function?

A

Muscle cells contain a large number of mitochondria, to generate a large amount of energy to enable movement to occur.

38
Q

What is the function of a root hair cell?

A

Root hair cells are involved in absorbing minerals and water.

39
Q

How are root hair cells adapted to their function?

A

They have a large surface area to absorb water and minerals.

40
Q

Compare the function of a phloem and a xylem?

A

> Phloem ==> Transports food across the plant.

> Xylem ==> Transports water across the plant.

41
Q

How are xylem and phloem cells adapted to their function?

A

Xylem and phloem cells are connected tightly together to form tubes to help transport their respective substances (water and food respectively).

42
Q

What are chromosomes?

A

Chromosomes are coiled up DNA.
It contains our genetic material.
Our genetic material determines our characteristics,

43
Q

How many chromosomes are there in a non-sex cell?

A

46 chromosomes (23 pairs)

44
Q

How many chromosomes are there in a sex cell? What is the clinical significance?

A

23 chromosomes (per gamete) - to ensure that the zygote obtains 46 chromosomes following fertilisation.

45
Q

In which part of the cell can your genetic material be found?

A

The nucleus

46
Q

What are the 2 main stages of the cell cycle?

A

1) Interphase
> This is the stage where the cell prepares itself for mitosis to occur e.g. it doubles the amount of DNA, it doubles the amount of protein within the cell, it doubles the amount of organelles e.g. mitochondria etc. This is so that the daughter cells obtain the same amount of cellular structures as the parent cell.
2) Mitosis
> This is the stage where the parent cell divides into 2 daughter cells.

47
Q

What is the point of mitosis?

A

Growth and repair

48
Q

What is the difference between mitosis and meiosis?

A

MITOSIS
> Carried out for growth and repair purposes e.g. during embryonic development or following an injury.
> Produces 2 daughter cells, that are genetically identical to the parent cell, across 1 cell division. Each daughter cell has 46 chromosomes and is therefore regarded as being diploid.
MEIOSIS
> Carried out to produce sex cells (gametes e.g. sperm and ovum).
>Produces 4 daughter cells (gametes) that are not genetically identical to the parent cell, across 2 cell divisions. Each daughter cell (gamete) has 23 chromosomes and is therefore regarded as being haploid.

49
Q

What happens during mitosis?

A

1) Chromosomes condense
2) Nuclear membrane breaks down
3) Mitotic spindles move towards the poles of each cell.
4) Chromosomes line up at the equator in its pairs.
5) Mitotic spindles send fibres which attach to each chromosome.
6) Mitotic fibres contract and therefore pull chromosomes (from its pairs) towards the poles of the cell.
7) Nuclear membranes reforms.
8) Cytoplasm divides creating 2 genetically identical daughter cells.

50
Q

What are the purposes of stem cells?

A

> Can be used to treat disease
1) Adult stem cells can be used to replace faulty blood cells in sick patients.
2) Embryonic stem cells can also be used to replace faulty cells in sick patients e.g. replace insulin producing cells in patients with Type 1 diabetes.
Can also be used in therapeutic cloning as well.
Can also be used for purposes of genetic research .

51
Q

What are some ethical concerns surrounding stem cell research?

A

1) The biggest ethical concern surrounding the use of stem cell relates to the use of embryonic stem cells. Many individuals feel that human embryos should not be experimented on as they have the potential for human life. However, other patients think that curing existing patient’s life is much more important than the right of the embryos.
2) It is also important to consider in this argument that the human embryos used by clinics are usually embryos that are unwanted or least likely to survive. However, there is still controversy as to whether it is right to decide which embryos live or die.

52
Q

What is the name of stem cells found in plants?

A

Meristem cells

53
Q

Where are meristem cells found within plants?

A

Behind the tip of the shoots.

54
Q

Why are meristem cells important?

A

Because they enable us to clone plants for example:
> they can be used to clone plants of rare species to prevent them from becoming wiped out.
> they can be used to clone plants with desired characteristics e.g. plants with disease resistance or plants with greater level of nutrition.

55
Q

What is diffusion?

A

Diffusion is the passive movement of molecules from a region of high concentration to a region of low concentration. Because molecules are going down a concentration gradient, no energy is required.

56
Q

What happens to the rate of diffusion when temperature is increased?

A

Rate of diffusion increases
> Higher temperature ==> Particles have greater kinetic energy and therefore move faster from a region of high concentration to a region of lower concentration.

57
Q

What is meant by osmosis?

A

Osmosis is the passive movement of water molecules across a partially permeable membrane from a region of high water concentration (diluted solution) to a region of low water concentration (concentrated solution).
Since water molecules are moving down a water concentration gradient, no energy is required, hence why the movement is described as being passive in nature.

58
Q

What is active transport?

A

Active transport is the movement of molecules from a region of low concentration to a region of high concentration. As the particles are moving against a concentration gradient, energy (in the form of ATP) is required.

59
Q

What are examples of active transport?

A

> Absorption of minerals via root hair cells from the soil. Remember that the mineral content in the soil is much lower than the mineral content in root hair cells.
Absorption of glucose from the gut into the bloodstream also requires active transport as well.

60
Q

What property do root hair cells have that enables them to be suitable for efficient mineral uptake?

A

Large surface area (have millions of hairs and has an elongated structure).

61
Q

What is a key property of exchange surfaces?

A

1) Large surface area to volume ratio - to increase the rate of exchange of substances across these surfaces.
2) Thin membranes - to allow easy diffusion to occur.
3) Have a lot of blood vessels that can maintain a concentration gradient.
4) Moist lining (only applies to alveolus).

62
Q

What are examples of exchange surfaces?

A

> The alveolus - this is where gaseous exchange occurs,

> The small intestines

63
Q

What happens at the alveolus?

A

> CO2 diffuses out of the bloodstream into the alveolus - we then expire (breathe out) the CO2.
O2 that we breathe in diffuses into the bloodstream. This helps to oxygenate our blood. This is important in making sure that our cells respire efficiently.

64
Q

What is the exchange surface within the small intestines called?

A

Villi

65
Q

What properties of villi make them suitable for exchange to occur?

A

1) Large surface area to volume ratio
2) Thin walls - single layer of cells on its surface.
3) Large blood supply to assist absorption.

66
Q

What is the role of stomata in plants?

A

To act as a site of gaseous exchange in plants.

67
Q

What factor determines the size of stomata in plants?

A

Guard cells - they determine the size of the stomata and therefore the rate of diffusion of oxygen and carbondioxide in plants.

68
Q

Why are leaves flat?

A

To increase the surface for which exchange can occur.

69
Q

Water vapour escapes leaves via what process?

A

Diffusion - thi sis because there is a lot of water inside the leaf and less of it in the air outside.

70
Q

What is the site of gaseous exchange in fish?

A

Gills

71
Q

Describe the gaseous exchange in the gills of fish?

A

Water (containing oxygen) enters the fish through its mouth and passes out through the gills. As this happens, oxygen diffuses from the water into the blood in the gills and carbondioxide diffuses from the blood into the water.

72
Q

What are gills made out of?

A

Gills are made up of thin plates called gill filaments.

73
Q

Why is it important that gill filaments are thin?

A

Because it helps to increase the surface area to volume ratio (to enable efficient gaseous exchange to occur).

Because it also helps to reduce the wall thickness as well to enable efficient gaseous exchange to occur.

74
Q

Describe the flow of water and the flow of blood in the gills of fish?

A

The flow of water occurs in the opposite direction to the flow of blood (hence the term countercurrent flow)..

75
Q

Why is countercurrent flow important?

A

To maintain the concentration gradient for efficient gaseous exchange to occur in fish. As a result of the countercurrent flow, the concentration of oxygen in the water is always higher than that in the blood so as much oxygen as possible can diffuse from the water into the blood.

Biology with NAJI the legend (5 decks)

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