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Biology > cell structure > Flashcards

cell structure Flashcards

1
Q

What is magnification?

A

The amount of times an image is magnified

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2
Q

What is resolution?

A

The ability to distinguish between two separate points

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3
Q

Magnification formula

A

Image size = actual size x magnification

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4
Q

Light microscopes

A
  • Use focused light through a objective and eyepiece lens to form and image
  • Max resolution of 200 nm
  • Max magnification of 2000x
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5
Q

Electron microscopes

A
  • Use electrons to form an image
  • Can be used to observe cell ultrastructure
    Two types:
  • Transmission
  • Scanning
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6
Q

Transmission Electron Microscopes

A

A beam of electrons transmitted through the specimen
- Black and white image
- Denser parts of the cell appear darker
- Max magnification = 500,000x
- Max resolution = 0.2nm

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7
Q

Scanning Electron Microscopes

A
  • A beam of electrons across the surface of a specimen
  • beams bounce of surface and electrons are detected forming an image
  • Create 3D image
    Max resolution - 3-10 nm
    Max magnification -500,000x
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8
Q

Laser Scanning Confocal Microscopes

A

Uses laser light to scan the specimen point by point. These points are then assembled by a computer, forming high resolution images with high contrast
Creates 3D image

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9
Q

How to calibrate an eyepiece graticule

A
  1. line up micrometer and eyepiece graticule
  2. Count how many divisions on the eyepiece fit into one division of the micrometer
  3. Each division on the micrometer is 10 micro meters. Can be used to calculate one division on the eyepiece graticule
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10
Q

what is the cell surface membrane

A
  • Mosaic fluid model - phospholipids, intrinsic proteins, extrinsic proteins, cholestrol and glycolipids
  • Partially permeable
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11
Q

what is the Cell wall

A
  • Freely permeable
  • Found in plant cells
  • Offers structural support to cells through cellulose in plants and peptidoglycan in bacteria
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12
Q

what is the Cytoplasm

A

Semi fluid substance that fills the interior of cells.
Contains organelles of the cells.
Site of many cellular processes such as metabolism

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13
Q

what are Mitochondria

A
  • Double membrane - inner membrane folded to form cristae
  • Matrix is the fluid inside the mitochondria that contains enzymes needed for aerobic respiration - also contains ribosomes and small circular DNA
  • Site of aerobic respiration, where glucose and oxygenn are used to produce ATP
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14
Q

what are Chloroplasts

A
  • Double membrane
  • Stroma - fluid found in chloroplasts
  • Grana - stack of thylakoids
  • thylakoids are fluid filled sacs containing photosystems which contain chlorophyll
  • site of photosynthesis
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15
Q

what are Ribosomes

A
  • formed in nucleolus
  • found freely or attached to RER
  • 80s ribosomes are found in eukaryotic cells
  • 70s in prokaryotes, mitochondria and chloroplasts
  • site of translation
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16
Q

what is the Rough Endoplasmic reticulum

A
  • Surface covered in ribosomes
  • Formed from continous folds of membrane continous of the nuclear envelope
  • Processes proteins made by ribosomes
17
Q

what is the Smooth Endoplasmic Reticulum

A
  • Does not have ribosomes
  • Involved in production, processing and storage of lipids, carbohydrates and steroids
18
Q

what is the Golgi apparatus

A
  • flattened sacs of membrane
  • Modifies proteins and lipids before packaging into golgi vesicles
  • the golgi vesicles then transport proteins and lipids to their required destination
19
Q

what is the Permanent vacuole

A
  • found in plant cells, surrounded by the tonoplast (selectively permeable membrane)
  • Vacoules in animals are not permenant and are much smaller
20
Q

what are Vesicles

A

Membrane bound sac used for transport and storage

21
Q

what are Lysosomes

A
  • Vesicles which contain hydrolytic enzymes
  • break down waste materials such as worn out organelles
22
Q

what are Centrioles

A
  • Hollow fibres made of microtubules
  • Two centrioles at right angles to each other form centrosomes , organises spindle fibres during cell division
23
Q

what is the Cytoskeleton

A
  • Defined as a network of fibres and proteins found in the cytoplasm of eukaryotic cells
  • Involved in intracellular transport, structural support, maintaining cell shape and cellular movements
  • Consists of: Microfillaments, Intermediate fillaments and microtubules
24
Q

what are Microfillaments

A

Thin rods composed of the protein actin
- Provides mechanical support
- Facilitates cell movement
- Involved in cytokinesis

25
Q

what are Intermediate Filaments

A
  • Made up of fibrous proteins
  • Provides mechanical strength and stability to cells and tissues
  • Support the nuclear envelopes shape and integrity
26
Q

what are Microtubules

A
  • Makes up the cytoskeleton
  • Made of a and b tubulin combined to form dimers, dimers are then joined to make profilaments - form a cylinder to make a microtubule
  • provide structural support and maintain cell integrity
  • used for intracellular transport
27
Q

what are Microvilli

A

Hair like projections made from microtubules
Allows movement of substances over the cell surface

28
Q

what is the Flagella

A

made of microtubules
Contract to provide cell movement

29
Q

what are Plasmids - prokaryotes

A

Small circular DNA molecules that can replicate independently of the bacterial chromosome

30
Q

what are Pili - Prokaryotes

A

Hair like structures that aid in attachment to surfaces or other cells.

31
Q

what is the Capsule - prokaryotes

A

Protective layer outside the cell wall, composed of polysaccharides or proteins

32
Q

what are Mesosomes - prokaryotes

A

Infoldings of the plasma membrane that are involved in cell division, DNA replication and respiratory processes

33
Q

What organelles are involved in protein synthesis

A

Nucleus
Ribosomes
Rough Endoplasmic reticulum
Golgi apparatus
Cell surface membrane

34
Q

Orgnalles roles in protein synthesis

A
  1. Nucleolus manufactures ribosomes which attach to RER
  2. Nucleus manufactures mRNA, which is needed by ribosomes to make proteins
  3. Ribosomes on RER make proteins
  4. The RER processes the proteins which are then sent into golgi vesicles
  5. Golgi vesicle is transported to Plasma membrane
  6. Vesicles fuse with the plasma membrane to secrete the finished protein product

Biology (9 decks)

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