B1:cells,microscopes And Specalised Cells Flashcards

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1
Q

What is the function of the cell wall?

A

The outer layer of a plant cell, gives strength and support. It is made of a carbohydrate called ‘cellulose’.

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2
Q

What is the function of the nuclues?

A

Controls the cell. Contains the genetic information called DNA

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3
Q

What is the function of the cell membrane?

A

Controls what enters and leaves the cell

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4
Q

What is the function of ribosomes?

A

Where protien synthesis takes place, making all the protiens needed in the cell.

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5
Q

What is the function of mitrochondria?

A

Site of respiration (release of energy from food)

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6
Q

What is the function of chloroplast?

A

They are found in all the green parts of a plant. They are green because they contain chlorophyll, which absorbs light so plants can photosynthesise (make food).

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7
Q

What is the function of the cytoplasm?

A

A liquid gel in which the organelles are suspended and where most of the chemical reactions ,needed for life, take place

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8
Q

What is the function of the large permanent vacuole?

A

Stores cell sap

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9
Q

In which type of cell would you find a cell wall?

A

Plant cell only

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10
Q

In which type of cell would you find ribosomes?

A

Both animal and plant cells have ribosomes

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11
Q

What are 2 differences between animal and plant cells?

A

-plant cells have chloroplast
-plant cells have a cell wall (where as a animal cell has neither)

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12
Q

How do you calculate total magnification?

A

Total magnification=Eyepiece lens x objective lens

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13
Q

Define the term resolution

A

Resolution is the ability to distinguish between 2 separate points in an image

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14
Q

Define the word ‘magnification’

A

Magnification is how much bigger an object is compared to it’s actul size. Can be calculated using the IAM triangle.

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15
Q

What is the IAM triangle?

A

I/A=M
I/M=A
MxA=I

I=image size
M=magnification
A=actul size of specimen

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16
Q

What type of microscope would be used to view small organelles (e.g ribosomes)?

A

Electron microscope

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17
Q

What type of DNA do prokaryotic cells have?

A

1 circular chromosome,Not enclosed by a nuclues.

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18
Q

What type of DNA do prokaryotic cells have?

A

Many linear chromosomes enclosed by a nuclues

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19
Q

How do you convert mm to um (micro-meters)?

A

X1000

5mm = 5000um

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20
Q

How do you convert mm to nm (nano-meters)?

A

X1000 and then by x1000 again (or just by a million)

5mm = 5000um (x1000)
5000um = 5,000,000nm (x1000)

21
Q

Convert 35mm into um

A

35 x 1000 = 35000um

22
Q

Convert 4.7 mm into nm

A

4.7 x 1,000,000 = 4,700,000nm

23
Q

Name 2 differences between prokaryotic cells and eukaryotic cells

A

-prokaryotic cells do not have a nuclues (where as a eukaryotic cell has)
-eukaryotic cells have genetic material enclosed in a nuclues
-a prokaryotic cell is a single-celled organism

24
Q

What is the function of a sperm cell?

A

Sperm cells contain a nucleus with half the DNA (23 chromosomes). Sperm cells fertilise the egg cell during sexual reproduction.

25
Q

What is the function of a nerve cell?

A

Transmits electrical impulses

26
Q

What is the function of a phloem cell in a plant?

A

Transports food (by translocation) from the leaves to ther parts of the plant.

27
Q

What is the function of a muscle cell?

A

When comtracted it gets shorter and if relaxed it gets longer. It controls all the movement in the body

28
Q

What is the function of a root hair cell?

A

Absorbs water and nutrients from the soil. The water and nutrients is then sent up through the rest of the plant.

29
Q

What is the function of a red blood cell?

A

Its job is to collect oxygen from the lungs and carry it around the body to cells so that it can be used for respiration. Also collects CO2 from cells and back to lungs for removal.

30
Q

What is the function of a palisade cell?

A

Found in the top half of a leaf. Its job is to carry out photosynthesis for the plant.

31
Q

What is the function of a xylem cell?

A

It is located in the roots,stems and leaves of a plant in the form of xylem vessels. Its function is to transport water from plant root hair cells to the leaves.

32
Q

Define the Focus

A

How sharp the image appears.

33
Q

Define a stain

A

Chemical used to colour the specimen (usally iodine)

34
Q

What is the objective lens

A

Lens nearest the object or objective

35
Q

What is the eyepiece lens?

A

Lens nearest the eye

36
Q

What is a eukaryotic cell?

A

Animal and plant cells are examples of these. Eukaryotic cells all have a cell membrane,cytoplasm,and genetic material that is enclosed in a nuclues. The genetic material is a chemical called DNA and this forms structures called chromosomes that are contained within the nuclues.

37
Q

What are prokaryotic cells?

A

A prokaryotic cell is a single-celled organism that lacks a nuclues and other membrane bound organelles (e.g mitrochondira). An example may be bacteria/bacterium. In a prokaryotic cell, the genetic material is not enclosed in a nuclues. The baterial chromosmes is a single DNA loop found free in the cytoplasm.

38
Q

1km=m
1m=cm
1cm=mm
1mm=um
1um=nm

A

1000m
100cm
10mm
1000um
1000nm

39
Q

How do light microscopes work?

A

Light microscopes use a beam of light to form an image of an object and the best can magnify around 2000 times (2000x)

40
Q

What is a electron microscope?

A

A electron microscope allows biologists to see and understand more about the subcellular structures inside cells. These instruments use a beam of electrons to form an image and can magnify objects up to around 2,000,000 times.

41
Q

The specimen is placed on a ….. which is mounted on the ……

A

Slide and stage

42
Q

What is the method for preparing a slide for a onion cell?

A

1)collect a sample of the cell you want to observe

2)Remove the inner skin of a layer of onion using forceps

3)place the thin slice onto a clean glass slide. Use forceps to keep the onion skin flat on glass slide

4)using a pipette, add 1 or 2 drops od dilute iodine solution on top of the onion skin (use a paper towel to mop up any spilled iodine (stain)

5)hold the coverslip by its sides and lay one edge of the coverslip onto the microscope slide near the specimen

6)lower the cover slip slowly so that the liquid spreads out

43
Q

What would you do if you want a better (clearer) image?

A

Use both coarse and fine focus

44
Q

How are sperm cells adapted for their function?

A

-streamlined head and long tail to aid swimming
-many mitrochondria (where respiration happens) which supply the energy to allow the cell to move
-the acrosome (top of the head) has digestive emzymes which break down the outer layers of membrane of the egg cell

45
Q

How are nerve cells adapted for their function?

A

-the axon is long,enabling the impulse to be carried along long distances
-having lots of extensions from the cell body (called dendrites) means branched connections can form with other nerve cells
-the nerve endings have many mitrochondria which supply the energy to make special transmitter chemicals called neurotansmitters. These allow the impulse to be passed from one cell to another.

46
Q

How are muscle cells adapted for their function?

A

-special protiens slide over each other,causing the muscle to contract
-Lots of mitrochondria to provide energy from respiration for contraction
-they can store a chemical called glycogen that is used in respiration by mitrochondria

47
Q

How are root hair cells adapted for their function?

A

-Have a large surface area due to root hairs,meaning more water can be absorbed by osmosis
-large permanent vacuole affects the speed of movement of water from soil to the cell
-have mitrochondria to provide energy from respiration for the active transport of mineral ions into the root hair cell

48
Q

How are xylem cells adapted for their function?

A

-xylem cells are hollow and joined end-to-end to form a continous tube so water and mineral ions can move through
-lignin is deposited in spirals which helps the cell walls which help withstand the pressure from the movement of the water

49
Q

How are phloem cells adapted for their function?

A

-cell walls of each phloem cell form structures called sieve plates when they break down,allowing the movement of substnaces from cell to cell
-have few organelles so food can move faster
-have a companion cell with mitrochondria to supply energy