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2.1-cells Flashcards

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1
Q

What are the advantages of optical microscopes?

A

relatively cheap
Easy to use
Portable + able to be used in the field as well as in labs
Able to be used used to study whole living organisms

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2
Q

What is the magnification of optical microscopes?

A

X2000

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3
Q

What is the resolution of optical microscopes?

A

200nm

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4
Q

How do u calculate total magnification ?

A

Magnifying power of objective lens x magnifying power of the eyepiece lens

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5
Q

What is the magnification of scanning electron microscopes?

A

Magnification: x200 000

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6
Q

What is the structure of the Golgi apparatus ?

A

Stack of membrane bound flattened sacs

Secretory vesicles being materials to and from the Golgi apparatus

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7
Q

What is the function of the Golgi apparatus ?

A

Proteins are modified here and then packaged into vesicles

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8
Q

what’s the function of the smooth endoplasmic reticulum?

A

1)SER contains enzymes that catalyse reactions involved with lipid metabolism, such as synthesis of:
Cholesterol
Steroid hormones
Phospholipids
2) SER is involved with absorption, synthesis, and transport of lipids from the gut.

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9
Q

Whats the nuclear envelope?

A

the DOUBLE MEMBRANE around the nucleus.

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10
Q

WHat is chromatin and what does it do?

A

chromatin=generic material
consists of DNA wrapped around histone proteins
when cell isn’t dividing, chromatin is spread out/extended
when cell’s about to divide, chromatin condenses+coils tightly into chromosomes.

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11
Q

What’s the structure of the nucleolus?

A

nucleolus has no membrane around it, it contains rNA.

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12
Q

What is a photomicrograph?

A

A photograph of the image seen using an optical microscope.

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13
Q

What are laser scanning microscopes sometimes called ?

A

Confocal microscopes

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14
Q

What are laser scanning microscopes used for ?

A

In the medical profession e.g.: to observe fungal filaments within the cornea of the eye of a patient with a fungal cornea infection to give a fast diagnosis so better treatment
Biological research

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15
Q

What can you use optical microscopes to observe ?

A
  • living organisms e.g. paramecium, amoeba
  • smear preparations of cheek and blood cells
  • thin sections of animal,plant, and fungal tissue
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16
Q

What is an all purpose stain ?

A

Methylene blue

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17
Q

What stains chromosomes And what colour ?

A

acetic orcein binds to DNA and stains chromosomes dark red.

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18
Q

What stains cytoplasm ?

A

eosin

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19
Q

What stains lipids ?

A

Sudan red

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20
Q

What is iodine used for in staining ?

A

Iodine in potassium iodide solution stains cellulose yellow and starch granules blue/black (these will look violet under the microscope )

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21
Q

What could be done to prepare specimens ?

A
  • dehydrating specimens
  • embedding them in wax to prevent distortion during slicing
  • using a special instrument to make v thin slides called sections; these are stained and mounted in a special chemical to preserve them.
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22
Q

What is the structure of the SER?

A

A system of membranes containing fluid filled cavities (cisternae) continuous with the nuclear membrane. There are no ribosomes on its surface.

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23
Q

What’s the function of the nucleolus?

A

It’s where the ribosomes are made.

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24
Q

Why is the nuclear envelope important ?

A

In some regions the outer and inner membrane fuse together. At these points some dissolved substances and ribosomes pass through. Pores in the nuclear envelope enable larger substances, like mRNA, to leave the nucleus and like steroid hormones to enter the nucleus.

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25
Q

What are the functions of the nucleus ?

A

1) control centre of cell
2) stores organism’s genome
3) transmits genetic information
4) provides the instructions for protein synthesis

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26
Q

What is the structure of the RER?

A

System of membranes containing fluid filled cavities (cisternae) continuous with the nuclear membrane. It’s coated with ribosomes.

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27
Q

What is the function of the RER?

A

Intracellular transport system: the cisternae form channels for transporting substances from one area of a cell to another. It provides a large surface area for ribosomes which assemble amino acids into proteins.

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28
Q

how do laser scanning microscopes work?

A

they use laser light to scan an object point by point and assemble by computer the pixel information into one image, displayed on a computer screen.

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29
Q

what is the resolution of electron microscopes?

A

0.004nm

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30
Q

how do scanning electron microscopes work?

A

electrons are fired from a cathode and don’t pass through the specimen, which is whole, but cause secondary electrons to “bounce off” the specimen’s surface and be focused onto a screen.

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31
Q

what has to happen to a specimen before it’s put in a scanning electron microscope?

A

placed in a vacuum and often coated with a fine film of metal.

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32
Q

what has to happen to a specimen before being put in a transmission electron microscope ?

A

chemically fixed by being dehydrated and stained with metal salts.

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33
Q

what are the disadvantages of electron microscopes?

A

large
v expensive
need lots of skill and training to use
metallic salt stains used may be potentially hazardous to user.
specimens have to be dead bc they’re put in a vacuum.

34
Q

how does a transmission electron microscope work?

A

beam of electrons fired from cathode passes through the specimen- some electrons pass through and are focused on the screen or photographic plate.

35
Q

how do you find magnification related to the sizes of the images?

A

magnification=image size/actual size

36
Q

what type of cells are eukaryotic?

A

animal
plant
fungal
protoctist (eg amoeba)

37
Q

what is the definition of resolution?

A

the smallest distance below which two discrete objects will be seen as one.

38
Q

what is the function of the SER?

A

contains enzymes that catalyse reactions involved with lipid metabolism, such as synthesis of:
1) cholesterol
2) lipids/phospholipids needed by the cell
3) steroid hormones
it’s also involved with absorption, synthesis, and transport of lipids from the gut.

39
Q

what is the structure of the mitochondria?

A
  • they may be spherical, rod shaped, or branched, and are 2-5 μm long.
  • surrounded by DOUBLE MEMBRANE with a fluid filled space between them.
  • inner membrane is highly folded into cristae-inner part of mitochondrion is a fluid filled matrix.
40
Q

what is the function of the mitochondria?

A
  • site of ATP production during aerobic respiration.

- self replicating

41
Q

where are mitochondria abundant?

A

cells where much metabolic activity takes place eg in liver cells and at synapses.

42
Q

what is the structure of the chloroplasts?

A

large organelles: 4-10 μm long.
surrounded by DOUBLE MEMBRANE
inner membrane continuous with stacks of thylakoids.
each stack of thylakoids is called a granum. the fluid filled matrix is called the stroma.
chloroplasts contain loops of DNA and starch grains.

43
Q

what is a thylakoid?

A

a flattened membrane sac which contains chlorophyll.

44
Q

what is a lamella and its context in chloroplasts?

A

lamella= a thin layer, membrane, or plate of tissue

intergranal lamellae connect grana

45
Q

what is the function of the chloroplast?

A

site of photosynthesis:

1) 1st stage of photosynthesis, when light energy is trapped by chlorophyll +used to make ATP, occurs in the grana. Water is also split to supply hydrogen ions.
2) 2nd stage of photosynthesis, when hydrogen reduces CO2 using ATP to make carbohydrates, occurs in the stroma.

46
Q

where are chloroplasts abundant?

A

in leaf cells, particularly the palisade mesophyll layer.

47
Q

what is the structure of the lysosomes?

A

small bags, formed by the golgi apparatus.
each is surrounded by a single membrane.
they contain powerful hydrolytic (digestive) enzymes.

48
Q

where are lysosomes abundant?

A

in phagocytic cells such as neutrophils and macrophages.

49
Q

what is the function of the lysosomes?

A

keep the powerful hydrolytic enzymes seperate from the rest of the cell.
lysosomes can engulf old cell organelles and foreign matter, digest them, and return them to the cell for reuse.

50
Q

what is the structure of the ribosomes?

A

small spherical organelles about 20nm in diameter
made of ribosomal rna
some remain free in cytoplasm and same attach to the rer.

51
Q

what is the structure of centrioles?

A

consist of 2 bundles of microtubules at right angles to eachother. the microtubules are made of tubulin protein subunits, and are arranged to form a cylinder.

52
Q

what is the function of centrioles?

A

before a cell divides the spindle, made of threads of tubulin, forms from the centrioles.

53
Q

how are centrioles involved in the formation of cilia and undulipodia?

A

before the cilia form, the centrioles multiply and line up beneath the cell surface membrane. microtubules then sprout outwards from each centriole, forming a cilium or undulipodium.

54
Q

what is a flagellum?

A

it helps movement in PROKARYOTIC cells.

55
Q

how does a flagellum work?

A

it’s made of flagellin, a spiral of protein that attaches to a disk at the base. When this rotates, using energy from ATP, the flagellum spins, propelling the cell.

56
Q

what is the function of cell walls?

A
  • provides strength and support
  • maintains cell’s shape
  • permeable and allows solutions to pass through.
  • strong and prevents plant cells from bursting when turgid.
57
Q

what are fungi’s cell walls made of ?

A

chitin

58
Q

what is the importance of the cytoskeleton?

A

1) providing mechanical strength to cells
2) aiding transport within cells
3) enabling cell movement.

59
Q

what are the similarities between prokaryotic and eukaryotic cells?

A 
both have:
plasma membrane 
cytoplasm
ribosomes
DNA and RNA
60
Q

what are the differences between prokaryotic and eukaryotic cells?

A

prokaryotic:

  • are much smaller
  • don’t have a nucleus, mitochondria, ERs, chloroplasts, or golgi ( no membrane bound organelles)
  • much less developed cytoskeleton w no centrioles.
  • their wall is made of peptidoglycan and not cellulose
  • smaller ribosomes
  • naked dna that’s not wound around histone proteins but floats free in the cytoplasm as a loop.
61
Q

what do some prokaryotic cells also have?

A
  • protective waxy capsule surrounding their cell wall.
  • small loops of DNA called plasmids
  • flagella
  • pili
62
Q

what are pili?

A

smaller hair like projections that enable the bacteria to adhere to host cells or to eachother, and allow the passage of plasmid DNA from one cell to another.

63
Q

what is the cytoskeleton?

A

network of protein structures within the cytoplasm

64
Q

what does the cytoskeleton consist of?

A

1) microfilaments, which are polymers of the protein actin; each one’s about 7nm in diameter.
2) intermediate filaments- about 10nm in diameter.
3) microtubules- straight, cylindrical, + made of protein subunits called tubulin- about 18-30nm in diameter.
4) cytoskeletal motor proteins: myosins, kinesins, and dyneins.

65
Q

what do cytoskeletal motor proteins do?

A

molecular motors

enzymes which have a site that binds to+allows hydrolysis of ATP as their energy source .

66
Q

what is magnification?

A

how much bigger an image appears compared with the original object.

67
Q

what is resolution?

A

the ability of an optical instrument to produce an image that shows fine detail clearly.

68
Q

what organelles are involved in the making and secreting of a protein in eukaryotic cells?

A

1) nucleus
2) nuclear envelope
3) ribosome
4) RER
5) golgi
6) plasma membrane

69
Q

what is the importance of the cytoskeleton?

A

support and mechanical strength
keep the cell’s shape stable
allow cell movement

70
Q

what is the eyepiece graticule?

A

measuring device-placed in the eyepiece of microscope and acts as ruler when you view object under microscope

71
Q

what is the stage graticule?

A

small scale placed on microscope stage used to calibrate value of eyepiece graticule at different magnifications.

72
Q

WHAT DO ANIMAL CELLS HAVE THAT PLANT CELLS DONT?

A

CENTRIOLES
LYSOSOMES
AND APPARENTLY GLYCOGEN GRANULES

73
Q

WHAT ARE 5 ROLES OF THE CYTOSKELETON?

A 
MOVES ORGANELLES
MOVES CHROMOSOMES
EXOCYTOSIS
STABILITY
CILIA/FLAGELLA MOVEMENT
74
Q

HOW DO PROTEINS GET RELEASED FROM A CELL?

A

VESICLES CONTAINING PROTEIN FUSE TO CELL SURFACE MEMBRANE

75
Q

WHAT’S SMALLER RIBOSOMES OR LYSOSOMES?

A

RIBOSOMES THEY’RE THE SMALLEST ORGANELLE

76
Q

IF YOU SAY CELL MEMBRANE AND YOU’RE TALKING ABOUT THE ACTUAL CELL MEMBRANE SAY…

A

CELL SURFACE MEMBRANE

77
Q

WHY WOULD ANIMAL CELLS BURST IF THERE’S TOO MUCH WATER IN THEM?

A

CELL MEMBRANE CAN’T STAND PRESSURE

78
Q

WHAT ARE THE ADAPTATIONS OF ROOT HAIR CELLS?

A 
CARRIER PROTEINS
LARGE SA
THE ROOT HAIRS/EXTENSIONS
THIN CELL WALL 
MORE MITOCHONDRIA
79
Q

why do root hair cells have thin cell walls?

A

speed up intake of water by osmosis.

80
Q

HOW MANY MICROMETERS IN A MM

A

1000

81
Q

HOW MANY NANOMETRES IN A MICROMETER

A

1000

82
Q

what are the features of images obtained from a TEM?

A 
2D
internal details visible
organelles visible
high magnification
high resolution

Biology (25 decks)

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