Microscope & Cells F4 Flashcards

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1
Q

Function of the eyepiece lens

A

to look through

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2
Q

Objective lens magnification

A

total magnification is: eyepiece x objective lens

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3
Q

Function of the stage

A

holds slide and specimen

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4
Q

Function of the focusing knob

A

moves position of lens or stage to focus

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5
Q

Function of the light source

A

provides light to form an image

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6
Q

Why do you use the lowest power of objective lens when using a light microscope?

A

The field of view is wider, allowing to see more of the cells on the slide and making it easier to find the specimen

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7
Q

How do electron microscopes work?

A

They pass beams of electrons through a specimen

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8
Q

What does resolution mean?

A

The ability of a microscope to see in great detail

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9
Q

How do you find the true size of a biological specimen?

A

size observed / magnification

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10
Q

How do you find the magnification of an image of a biological specimen?

A

size observed / actual size

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11
Q

How do you find the magnification of an image?

A

measured length of scale line / given length of scale line

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12
Q

How do you prepare a slide of plant cells?

A
  • take a clean slide
  • lift small piece of tissue
  • add drops of iodine solution
  • view slide at low power
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13
Q

Why is iodine solution added?

A

To stain the cells and make them show clearly

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14
Q

Why does the piece of tissue need to be thin?

A

To allow light from the source to pass through the cells

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15
Q

How do you prepare a slide of animal cells?

A
  • rub clean cotton bud on inside of cheek
  • smear cotton bud on microscope slide
  • add drop of methylene blue stain
  • lower coverslip
  • view on lowest power
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16
Q

What is the function of the vacuole?

A

contains cell sap and helps cell keep its shape

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17
Q

What is the function of the cell wall?

A

provides support to the cell

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18
Q

What is the function of the chloroplast?

A

contains chlorophyll to trap light during photosynthesis

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19
Q

What is the function of the nucleus?

A

control centre of cell containing genetic information of cell

20
Q

What is the function of the chromosomes?

A

carry genetic material in genes

21
Q

What is the function of the nuclear membrane?

A

boundary of the nucleus

22
Q

What is the function of the cytoplasm?

A

where all chemical reactions take place

23
Q

What is the function of the cell membrane?

A

selectively permeable, controls what enters and leaves the cell

24
Q

What is the function of the mitochondria?

A

site of cell respiration

25
Q

What are stem cells?

A

Undifferentiated cells that divide by mitosis to become a specialised cell

26
Q

What are the properties of stem cells?

A
  • can differentiate into any specialised cell types

- continue dividing by mitosis to produce more stem cells

27
Q

Where can you find stem cells?

A
  • embryos
  • placenta
  • umbilical cords
  • bone marrow
28
Q

Why are embryos favoured over adult stem cells?

A
  • easy to grow
  • easy to extract
  • able to develop into many different cell types
29
Q

What are the ethical issues in using embryos for stem cells?

A
  • against some peoples religions

- some believe its against the human rights of the embryo

30
Q

What is peer review?

A

when different scientists work together in teams to share ideas and results

31
Q

Where do stem cells originate in plants?

A

from meristems at the apical bud of the shoot

32
Q

Describe the procedure of using stem cells for Leukaemia

A
  • chemo destroys cancerous white blood cells
  • patient is given transplant of bone marrow from healthy matching donor
  • donor cells multiply to produce healthy blood cells
33
Q

How else can stem cells be used in medicine?

A

making retina cells - blindness

making brain cells - parkinson’s

34
Q

What are the potential risks of using stem cells to cure Leukaemia?

A
  • chemo leaves patient with no immune system
  • viruses / diseases may be transferred
  • tumours may develop of unwanted cells
35
Q

What are 3 examples of organ systems in humans?

A
  • digestive
  • nervous
  • reproductive
36
Q

What are the functions of the digestive system?

A

breaks down large insoluble foods molecules into small soluble molecules (stomach)

37
Q

What are the functions of the nervous system?

A

makes responses and responds to stimuli (brain)

38
Q

What are the functions of the reproductive system?

A

production of young (uterus)

39
Q

What are the benefits of having organ systems?

A
  • helps transport substances through the body better
  • helps communication between cells
  • improves gas exchange
40
Q

What is surface area to volume ratio?

A

As the size of the organism increases, its surface area to volume ratio decreases

41
Q

What are the adaptions of exchange surfaces?

A
  • large exchange surface area by having a folded surface

- thin exchange surface for short diffusion distance

42
Q

How is the efficiency of exchanged maximised?

A
  • good blood supply do to the capillary networks

- distribute exchanged materials to all cells

43
Q

What is diffusion?

A

The movement of molecules from a high to low concentration

44
Q

What is the process of diffusion in the lungs?

A

Blood continues to take in oxygen from alveolar air spaces provided by concentration of oxygen there is greater than in the blood

45
Q

What factors affect the rate of diffusion?

A
  • temperature (high temp. speeds up movement by increasing kinetic energy)
  • surface area (greater area for molecules to move through)