mr Allsop- cell structure Flashcards

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1
Q

how do electron microscopes work

A

electron beams have shorter wavelengths than light resulting in higher resolution.

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2
Q

what is resolution

A

the smallest distance between two points where they both look like two separate points.

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3
Q

what is magnification

A

making an image appear larger.

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4
Q

what is calibration

A

how many lines on the eyepiece graticule (small ruler) can fit into large ruler (stage micrometer)

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5
Q

what is a transmission electron magnification (TEM)

A

beam of electrons fired through specimen
magnification-1,000,000 image-2D
resolution-0.5nm cost-expensive
colour-none sample-dead
have to be installed, take up a lot of space, training to use, slide and sample prep

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6
Q

what is scanning electron magnification

A

beam of electrons sent across surface of specimen. reflected electrons collected.
3D image mag- 150,000 expensive only dead sample
resolution is 3-10nm
no colour

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7
Q

light microscope (mag, resolution, image etc)

A

magnification- x2000 natural colour/stain
resolution-200nm no vacuum living/dead
2D image cheaper
accessible, less training, slide prep easy, no vacuum- living/dead

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8
Q

laser scanning confocal microscopy

A

marked with fluorescence: absorbs and re-radiates light which has a longer wavelength and lower energy- filtered through a pinhole aperture.
very high resolution images.
non-invasive, currently used to diagnose eye disease and development of drugs.

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9
Q

dry mount

A

solid specimen viewed not with water.
can be viewed whole or in slices.
eg. pollen ,hair ,dust.

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10
Q

wet mount

A

specimen suspended in water.
cover slip added at angles (prevent bubbles)
allows viewing of small aquatic organisms.

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11
Q

squash slides

A

wet mount prepared then blotted dry and gently applied pressure to squash sample, thin enough to transmit light.

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12
Q

smear slides

A

apply thin ,even coat using edge of slide and add cover slip. eg. blood cells

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13
Q

what is staining ?

A

increases contrast because components take up the stain so is easier to identify.

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14
Q

+VE dyes

A

attracted to -ve dye ,staining them blue

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15
Q

-VE dye

A

repelled by -ve dye so dye stays outside of cell and remains unstained and stands out against stained background.

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16
Q

differential staining and gram p/N

A

distinguishes between two types of organisms.
gram positive-thick cell wall- dye is retained gram negative- thin wall so dye leaves and is a less visible image.

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17
Q

steps to differential dye

A

1) crystal violet applied to specimen
2)iodine added, fixing dye
3)slide washed positive: blue/purple
negative: red

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18
Q

what do membranes do ?

A

surround organelle keeping components inside.
allows selected molecules to move in and out.
allows cellular processes to occur separately
allow cell to change shape

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19
Q

what is chromatin?

A

inside nuclear membrane.
spread out DNA before becoming chromosomes.

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20
Q

what and where the nucleolus ?

A

where ribosomes are made and synthesised into proteins.

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21
Q

what are nuclear pores?

A

holes in membrane where MRNA (copy of DNA) leaves

22
Q

translation of ribosomes (making)

A

attach to rough endoplasmic reticulum (RER)
mrna is transported by cisternae.

23
Q

what is cisternae

A

flattened sacks of the RER where ribosomes attach

24
Q

What is the SER

A

Smooth endoplasmic reticulum.
Carbohydrate and lipids synthesis.
No ribosomes.

25
Q

How is SER a transport vesicle

A

Membrane of ser continually buds off which is a package of proteins.

26
Q

What is Golgi apparatus

A

Modifies and repackages molecule for specific destination. Fuses with cisternae at one end but buds off at another.

27
Q

Golgi vesicle (transport)

A

Some are lysosomes which contain enzymes that break down old organelles/infectious bacteria.
Some go elsewhere but some rejected by exocytosis (leaving membrane )

28
Q

What is in a mitochondrion

A

Inner layer - folds inwards to form cristae which projects a liquid Called matrix.

29
Q

What is in the inner membrane of mitochondrion

A

Coated with enzymes, which catalyse the reactions of aerobic respiration to produce ATP.

30
Q

What are the microtubules

A

Like train tracks.
Main component of cells cytoskeleton.
Connects all organelles together to keep them in place.

31
Q

What are centrioles

A

Coordinate the growth microtubules
Example of microtubule organising centre (MTOC) ( like poles in metaphase)

32
Q

What is the cytoskeleton?

A

Network of fine actin filaments. Work with microtubules. (Like scaffolding it gives structure)

33
Q

What is cilia

A

Short hair-like outgrowths that help with wafting things out like mucus.

34
Q

Flagella

A

Long hair-like outgrows surrounded by the plasma membrane. Two microtubules in centre and 9 pairs on the outside contract causing it to move.

35
Q

Plant cell wall

A

Made of cellulose- carbohydrate store.
Pores called plasmodesmata which connect two cells together to enable transport materials.

36
Q

Everything about Chloroplasts

A

Double membrane , thylakoid (flattened sacs) stack up to form grana. The thylakoid is site of photosynthesis.
Filled with liquid called stroma.

37
Q

What is the lamellae and where is it

A

It’s in the chloroplast and is a string like membrane that links together grana.

38
Q

Everything about permanent vacuoles in a plant cell.

A

Membrane called Tonoplast.
Filled with Sap that keeps cell turgid.
Vacuole created turgour pressure that keeps it firm.

39
Q

What is the membrane around starch called

A

Amyloplast.

40
Q

What is the s of ribosome in prokaryotic vs eukaryotic

A

Prokaryotic- 70s ribosome
Eukaryotic-80s ribosome

41
Q

Cell wall of prokaryotes vs eukaryote

A

Prokaryotes- Peptidoglycan
Eukaryote - cellulose/chitin

42
Q

What do bacteria make in the mesosomes

A

ATP

43
Q

What is a mesosome

A

Membrane that’s folded in on itself (invagination)

44
Q

What does the nucleoid do in prokaryotic cells

A

Controls cell including reproduction. Contains most genetic material where transcription and replication of DNA takes place.

45
Q

What are Bacterial capsules

A

Mucous like protective layer so hides antigens on surface to hide from immune system. Capsule composed of polysaccharides.

46
Q

What is flagella powered by

A

Protein motors

47
Q

What is pili

A

Hollow protein structures used during bacterial conjugation( genetic material transferred from one bacterium to another)

48
Q

What is a plasmid and where is it used

A

Small loop of DNA that is reciplicated of bacteria’s DNA. Used in genetic engineering.

49
Q

What do lysosomes do?

A

Contain digestive enzymes and break down and recycle cellular waste and unwanted material they digest the large molecules of nutrients in the cell and change them into structurally simpler substances. White blood cells use the digestive enzymes in the lysosomes to digest and destroy the pathogens which invade the cell.

50
Q
A
51
Q
A