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BIOLOGY AS > Mod 2 Chap 2: Cell Structure and Microscopy > Flashcards

Mod 2 Chap 2: Cell Structure and Microscopy Flashcards

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1
Q

How do you convert from mm to micrometers?

A

X 1000

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2
Q

How do you convert from micrometers to mm?

A

divide by 1000

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3
Q

How do you convert from micrometers to nm?

A

X 1000

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4
Q

How do you convert from nm to micrometers?

A

Divide by 1000

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5
Q

What does epu stand for?

A

Eye piece units across

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6
Q

What is the equation needed for magnification calculations?

A

I
AM

I = image size
A = actual size
M = magnification

So I = A x M
A = I / M
M = I / A

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7
Q 
Answer these questions for a light/ optical microscope:
Source of image:
How the beam is focused:
Max effective magnification:
Max resolution:
Can a live specimen be used:
Section / external view:
Cost:
Staining of specimen required:
A 
Source of image: BEAM OF LIGHT
How the beam is focused: LENSES
Max effective magnification: X 1500
Max resolution: 200 nm
Can a live specimen be used: YES
Section / external view: SECTION
Cost: CHEAP
Staining of specimen required: NO
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8
Q 
Answer these questions for transmission electron microscope (TEM):
Source of image:
How the beam is focused:
Max effective magnification:
Max resolution:
Can a live specimen be used:
Section / external view:
Cost:
Staining of specimen required:
A 
Source of image: ELECTRON BEAM
How the beam is focused: ELECTROMAGNETS
Max effective magnification: X 500,000
Max resolution: 0.2nm
Can a live specimen be used: NO
Section / external view: SECTION
Cost: EXPENSIVE
Staining of specimen required: YES WITH METAL SALTS
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9
Q 
Answer these questions for a scanning electron microscope (SEM):
Source of image:
How the beam is focused:
Max effective magnification:
Max resolution:
Can a live specimen be used:
Section / external view:
Cost:
Staining of specimen required:
A 
Source of image: ELECTRON BEAM
How the beam is focused: ELECTROMAGNETS
Max effective magnification: X 100,000
Max resolution: 10 nm
Can a live specimen be used: NO
Section / external view: EXTERNAL
Cost: EXPENSIVE
Staining of specimen required: COATED WITH GOLD
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10
Q

List the four types of microscope

A

Scanning Electron Microscope
Light / Optical
Transmission Electron Microscope
Laser

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11
Q

Define Magnification:

A

How many times larger the image is than the actual size of the object being viewed.

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12
Q

Define Resolution:

A

The ability to see individual objects as separate entities.

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13
Q

Which types of microscope can produce 3D images?

A

Scanning (SEM)

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14
Q

Which microscope uses fluorescent dyes to stain specimens?

A

Laser scanning

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15
Q

What are the organelles present in animal cells?

A 
Plasma membrane
Nucleus
Nucleolus
Nuclear envelope
Nuclear pore
Peroxisome
Ribosome
Golgi complex
Lysosomes
Secretory vesicle
Mitochondrion
Cytoplasm
Centrioles
Cytoskeleton - filaments
Microtubules
Smooth endoplasmic reticulum
Rough endoplasmic reticulum
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16
Q

What are the organelles present in plant cells?

A 
Plasma membrane
Cytoplasm
Mitochondria
Cytoskeleton: micro tubules, filaments
Nucleus
Nucleolus
Nuclear envelope
Nuclear pore
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Golgi complex
Peroxisome
Cell wall
Chloroplast
Permanent vacuole: tonoplast
Plasmo desmata
Ribosomes
17
Q

What is the function of the centrioles?

A

Component of the cytoskeleton involved in assembly and organization of spindle fibers during cell division

18
Q

Describe the preparation and examination of slides used in light microscopy.

A
  • sample placed on a slide + allowed to air dry
  • then heat fixed by passing through a flame
  • specimen then adheres to microscope slide + takes up stains
19
Q

Describe the various methods in which samples and specimens can be prepared for examination by light microscopy.

A
  • dry mount: specimen place onto slide dry + covered with a slip
  • wet mount: specimens suspended in liquid such as water + covered with a slip
  • squash slides: wet mount is prepared, cover slip is pressed down with a lens tissue, damage to cover slip can be avoided using two microscope / squash slides
  • smear slides: edge of a slide used to smear sample on another slide, cover slip then placed on top.
20
Q

Describe the importance of the cytoskeleton in terms of its structure.

A
  • it’s a network of protein structures within cytoplasm

CONSISTS OF:

  • rod like MICROFILAMENTS made of subunits of protein actin, they are polymers of actin.
  • INTERMEDIATE FILAMENTS about 10nm in diameter
  • MICROTUBULES that are straight and cylindrical, made of subunits of protein tubulin
  • CYTOSKELTAL MOTOR PROTEINS: myosins, kinesins, and dyenins are molecular motors, they are enzymes that allow hydrolysis of ATP as the energy source.
  • cytoskeleton is present in all eukaryotic cells
  • network of fibers necessary for shape and stability of cell
  • holds organelles in place
  • controls cell movement and movement of organelles within cells
21
Q

Describe the importance of the cytoskeleton in terms of cell movement.

A
  • movement of cells like phagocytes depends on activity of actin filaments in cytoskeleton
  • filament lengths change w/ addition + removal of monomer subunits. (Rate these subunits added is diff at each end of filament)
  • so at certain concentrations, subunits added at one end + removed at other, called ‘treadmilling’, causing cells to move in a particular direction.
22
Q

Describe the differences in structure and ultra structure of prokaryotic and eukaryotic cells.

A

Eukaryotic Prokaryotic

-Has membrane bound organelles. -Does not
-Has a nucleus. -Does not
-Large ribosomes. -Small ribosomes
-DNA on linear chromosomes. -DNA on circular
chromosomes
-DNA within cytoplasm. -DNA within nucleus
-ATP production in folded regions of. -ATP production in
cell membrane called mesosomes. mitochondria
-cellulose based cell wall. -peptidoglycan based
cell wall
- may have undulipodia. - may have flagella
(Cilia and flagella)

23
Q

What is differential staining?

A

It can distinguish between two types of organisms that would otherwise be difficult to differentiate between different organelles of a single organism within a tissue sample.

24
Q

What techniques can be used when staining samples in microscopy?

A

Gram Stain Technique - separates bacteria into two groups

Acid-fast technique - differentiates species of Mycobacterium from other bacteria.

25
Q

What is the function of ribosomes?

A
  • constructed of RNA molecules made in nucleolus

- site of protein synthesis

26
Q

What is the function of chloroplasts?

A
  • responsible for photosynthesis in plant cells
  • have internal network of membranes forming flattened sacs called thylakoids, several thylakoids stacked together = granum (plural grana)
  • grana contain chlorophyll pigments, where light dependant reactions occur in photosynthesis.
  • contain DNA + ribosomes so can make own proteins
27
Q

What is the function of cilia?

A
  • stationary cilia present on surface of many cells, have important functions in sense organs e.g. nose.
  • mobile cilia beat rhythmically to create current + move fluids or objects away from cell
  • cilia = hair like
  • flagella = whip like
28
Q

What is the function of the Golgi apparatus?

A
  • role in modifying proteins + packaging them into vesicles, (secretory vesicles if proteins are destined to leave cell /lysosomes, which stay in cell).
29
Q

What is the function of the rough endoplasmic reticulum? Describe it.

A
  • has ribosomes bound to surface + is responsible for synthesis + transport of proteins
  • is network of membranes enclosing flattened sacs called cisternae
  • connected to outer membrane of nucleus
30
Q

What is the function of the smooth endoplasmic reticulum? Describe it.

A
  • responsible for lipids and carbohydrate synthesis and storage
  • a network of membranes enclosing flattened sacs called cisternae
  • connected to outer membrane of nucleus
31
Q

What is the function of lysosomes and Peroxisomes?

A

Lysosomes:

  • contain hydrolytic enzymes, responsible for breaking down waste materials in cells
  • responsible for breaking down pathogens ingested by phagocytic cells
  • play important role in programmed cell death or ‘apoptosis’

Peroxisomes:
- contain same digestive enzymes (hydrolytic enzymes) to get rid of nasty toxins.

32
Q

What is the function of the nucleus, nucleolus, nuclear envelope and nuclear pores?

A

Nucleus:
- contains coded genetic material in form of DNA molecules

Nuclear envelope:
- contains double membrane w/ DNA to protect DNA from damage in cytoplasm

Nuclear pores:
- allow molecules to move into + out of nucleus

33
Q

What is the function of mitochondria?

A
  • essential organelles, site of final stages of cellular respiration
  • are where molecule ATP makes energy stores in bonds of complex organic molecules for cell to use
  • can produce their own enzymes + reproduce themselves
34
Q

What is the function of the cell wall?

A
  • made of cellulose
  • permeable so allow substances into + out of cells through them
  • give plant cells shape
  • acts as defense mechanism, protecting cell contents against invading pathogens
  • present in all plant cells
35
Q

What is the function of a vacuole?

A
  • important in maintenance of turgor (so contents of cell push against cell walls + maintain rigid structure)
  • membrane of vacuole, (tonoplast), = selectively permeable so only allows some molecules to pass through it
36
Q

What is the function of the centrioles?

A
  • composed of microtubules
  • component of cytoskeleton
  • two associated centrioles form centrosome, which is involved in assembly and organization of spindle fibres during cell division.
37
Q

Describe the process of protein synthesis.

A
  • gene w/ coded instructions for the protein is transcribed into a length of messenger RNA (mRNA)
  • many copies of mRNA made + pass out of pores in nuclear envelope
  • mRNA attaches to a ribosome, which is attached to RER, ribosome reads instruction to assemble protein insulin (process called translation)
  • insulin molecules pass into cisternae of RER + along these hollow sacs
  • insulin molecules ‘pinched off’ in vesicles + travel via microtubules + motor proteins to Golgi apparatus
  • vesicle fuses w/ Golgi apparatus
  • Golgi apparatus processes + packages insulin molecules ready for release
  • packaged insulin molecules ‘pinched off’ in vesicles from Golgi apparatus + move towards plasma membrane
  • vesicle fuses w/ plasma membrane
  • plasma membrane opens to release insulin molecules outside.

BIOLOGY AS (12 decks)

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