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Josh Lee Biology > Topic 1 - Cell Biology > Flashcards

Topic 1 - Cell Biology Flashcards

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1
Q

What are eukaryotic cells?

A

Eukaryotic cells are complex and include animal and plant cells.

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2
Q

What are prokaryotic cells?

A

Prokaryotic cells are small and simple. Eg bacteria

A prokaryote is a prokaryotic cell.

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3
Q

What is the function of the nucleus?

A

Contains genetic material and controls activities of the cell

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4
Q

What is the function of cytoplasm?

A

Gel-like substance where most chemical reactions happen. Contains enzymes which control these reactions.

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5
Q

What is the function of cell-membrane?

A

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

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6
Q

What is the function of mitochondria?

A

Where respiration takes place

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7
Q

What is the function of ribosomes?

A

Where proteins are made in the cell

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8
Q

What is the function of the cell wall?

A

Made of cellulose. Supports the cell and strengthens it.

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9
Q

What is the function of the vacuole?

A

Contains cell sap, a weak solution of sugar and salts.

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10
Q

What is the function of chloroplasts?

A

Where photosynthesis takes place.

Contains lots of chlorophyll which is needed to absorb light for photosynthesis.

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11
Q

Do bacteria cells contain a nucleus?

A

No, instead they have a single strand of DNA.

They also have other small rings of DNA called plasmids.

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12
Q

Why do we use microscopes?

A

Microscopes let us see things that we cant see with the naked eye.
They let us see individual cells and sub cellular structures.

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13
Q

Whats the difference between a light microscope and electron microscope?

A

Light microscopes use light and lenses to magnify an image.

Electron microscopes use electrons instead of light and have a a much higher magnification and resolution.

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14
Q

Whats the definition of resolution?

A

Resolution is the ability to distinguish between 2 points.

A higher resolution gives sharper images.

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15
Q

Whats the formula for magnification?

A

Magnification = Image size / Real size

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16
Q

What is the process by which cells become specialised for its job?

A

Differentiation

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17
Q

What does most differentiation occur?

A

As an organism develops.

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18
Q

What are undifferentiated cells called?

A

Stem cells.

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19
Q

Whats the function and features of sperm cells?

A

Function of sperm is to get male DNA to female DNA.

Has a long tail and streamlined head to help it swim to the egg.
Lots of mitochondria in the cell to provide energy needed.
Carries enzymes in its head to digest through the egg cell membrane.

20
Q

Whats the function and features of nerve cells?

A

Function is to carry electrical signals from one part of the body to another.

Cells are long and have branched connections to form a network throughout the body.

21
Q

Whats the function and features of muscle cells?

A

Function is to contract quickly.

They are long (more space to contract) and contain lots of mitochondria to generate the energy needed to contract

22
Q

What is the function and features of root hair cells?

A

Function is to absorb water and mineral ions from the soil.

They grow into long hairs which give the plant a larger surface area

23
Q

What is the function and features of xylem and phloem cells?

A

Function is to transport substances such as food and water around the plant.

To form tubes, the cells are long and joined end to end.
Xylem cells are hollow and phloem have few sub cellular structures.

24
Q

What contains genetic information?

A

Chromosomes

25
Q

How many pairs of chromosomes does a human cell have?

A

23 pairs

26
Q

What are the steps of the cell cycle?

A

1) DNA spreads out
2) Cell grows and increases in sub cellular structures
3) It duplicates its DNA and forms X-shaped chromosomes

4) Chromosomes line up at center of cell and cell fibres pull them apart. Two arms of each chromosome go to opposite ends of the cell.
5) Membranes form round each of the sets of chromosomes. They become nuclei of 2 new cells.
6) Lastly, cytoplasm and cell membrane divides .

27
Q

How do prokaryotic cells replicate?

A

Through binary fission

28
Q

What are the steps for binary fission?

A

1) DNA and plasmids replicate
2) Cell gets bigger and the 2 circular DNA strands move to opposite ends.
3) Cytoplasm begins to divide and new cell walls begin to form
4) Cytoplasm divides and 2 new cells are produced.

29
Q

What are functions of stem cells?

A

Medicine:

Adult stem cells transferred from bone marrow of healthy person can replace faulty blood cells in a person that receives them.

Embryonic stem cells can be used to replace faulty cells in sick people. Eg insulin producing cells for diabetics.

Therapeutic cloning where embryo is made to have same genes as patient so stem cells wouldnt get rejected.

30
Q

What is a risk of using stem cells in medicine?

A

Stem cells grown in a lab could become contaminated with a virus and spread onto the patient.

31
Q

What are some reasons people have as to why they are against stem cell research?

A

1) They feel human embryos shouldnt be used for experiments as they are potential life.(Counter is that curing existing patients who are suffering is more important)(Embryos used are usually unwanted ones)
2) Scientists should concentrate more on finding and developing other source of stem cells, so theres no need to use embryos.

32
Q

How can stem cells be used to clone plants?

A

In plants, stem cells are found in the meristems.
These stem cell can be used to produce clones of plants quickly and cheaply.

It may be ideal for a farmer to get desired features like disease resistance.

33
Q

What is diffusion?

A

Diffusion is the spreading out of particles from an area of higher concentration to an area of lower concentration.

34
Q

What increases diffusion rate?

A

How big the concentration gradient (difference in concentrations) is.

Temperature

35
Q

What is osmosis?

A

Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of lower water concentration.

36
Q

What is a partially permeable membrane?

A

A membrane with very small holes in it. Only tiny molecules like water can pass through and not big molecules like sucrose.

37
Q

What is active transport?

A

Active transport is when substances are absorbed AGAINST a concentration gradient eg from lower to higher concentration.

38
Q

How does active transport work for plants?

A

Allows plants to absorb minerals from a very dilute solution to a highly concentrated solution.
Active transport needs energy from respiration to work.

39
Q

How does active transport work in humans?

A

Allows nutrients to be taken into the blood from the gut even if fhe gut has a lower concentration.

Example of the nutrient is glucose

40
Q

What depends of Surface Area : Volume ?

A

How easy it is for an organism to exchange substances with irs environment.

41
Q

Why can single celled organisms diffuse substances straight into the cell?

A

They have large surface area compared to volume

42
Q

What are adaptations of exchange surfaces?

A

Thin membrane - Short distance for substances to diffuse.

Large surface area - Lots of a substance can diffuse at once.

Lots of blood vessels - Get stuff into and out of blood quickly.

Ventilated - Air moves in and out

43
Q

How does gas exchange happen in the lungs?

A

Alveoli in the lungs are specialised to maximise diffusion of O2 and CO2.

They have large surface area.
Moist lining for dissolving gases.
Thin walls.
Good blood supply

44
Q

How does gas exchange work in the small intestine?

A

Small intestine inside is covered with millions of villi.
They increase surface area so digested food is absorbed more quickly into the blood.

They have single layer of surface cells.
Good blood supply to assist quick absorption.

45
Q

How does gas exchange happen in leaves?

A

Stomata on the underneath of a leaf allow CO2 in and O2 and water vapour out.
Stomata size is controlled by guard cells which adapts to how juch water is being lost.

Flattened shape of leaf increases area of exchange surface.
Air spaces inside leaf also increase area of surface so more chance of CO2 getting into cells.

46
Q

How does has exchange work in fish?

A

Gills is the gas exchange surface.
Water (containing oxygen) goes into mouth and passes out through gills.
Each gill is made up of gill filaments with big surface areas.
Gill filaments have lots of lamellae which increase surface area even more.
Lamellae have lots of blood capillaires to speed up diffusion.
Also have thin surface layer of cells to minimise distance.
Blood and water flow in opposite directions. Blood through lamellae and water over lamellae. Maintains large concentration gradient.

Josh Lee Biology (6 decks)

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