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OCR AS/A Level Biology Context > module 2.1.1 - cell structure > Flashcards

module 2.1.1 - cell structure Flashcards

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1
Q

what is the magnification for a TEM

A

300,000 - 1,000,000x

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2
Q

what is the resolution for a TEM

A

0.05 - 1nm

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3
Q

what can be viewed under a TEM

A

detailing organelle ultrastructure (in 2D), dead, black and white

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4
Q

what is meant by the term magnification

A

the ratio of a image size to object size

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5
Q

what is meant by the term resolution

A

the ability to distinguish between 2 objects that are close together. the ability to provide detail in the image

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6
Q

what is the equation for magnification

A

magnification=image size/actual size

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7
Q

what is the magnification of a light microscope

A

1000 - 2000x

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8
Q

what is the resolution of a light microscope

A

50 - 200nm

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9
Q

what can be viewed under a light microscope

A

live tissues and cells

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10
Q

what is the magnification of a SEM

A

50,000 - 500,000x

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11
Q

what is the resolution of a SEM

A

0.4 - 20nm

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12
Q

what can be viewed under a SEM

A

the surface of cells and organelles(dead), black and white

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13
Q

what is the magnification for a laser scanning confocal microscope (LSC)

A

1,000 - 2,000x

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14
Q

what is the resolution of a LSC

A

50 - 200nm

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15
Q

what can be viewed under a LSC

A

object at a certain depth within a cell (in 2D/3D) and coloured

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16
Q

what is the meaning of staining

A

the application of coloured stains to the tissue or cell

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17
Q

what does staining do

A

contrast is higher, clearer image can be obtained, increases contrast so that the object can be seen more clearly

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18
Q

what are some examples of organelles and their staining

A

nile blue - nucleus
acetin orcein - chromosomes
eosin - cytoplasm
sudan red - lipids
iodine in potassium iodide solution stains the cellulose in plant cell walls yellow and starch granules blue/black

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19
Q

what is the function of the mitochondria

A

site of aerobic respiration

20
Q

what is the structure of the mitochondria

A

it is surrounded by 2 membrane. the inner membrane layer folds inwards to form cristae. the cristae project into a liquid called the matrix

21
Q

what is the function of the golgi apparatus

A

modifies and (re)packages proteins made from the nucleus and it goes to the cell surface membrane. often adds a carbohydrate group.

22
Q

what is the structure of the golgi apparatus

A

a stack of membrane bound flattened sacs. its membrane surrounds an area of fluid where the complex molecules are stored and changed

23
Q

what is the function of RER

A

some of the proteins will be secreted by the cell whilst the others will be placed on the surface of the cell membrane

24
Q

what is the structure of RER

A

consists of a series of flattened membrane bound sacs called cisternae. they are studded with ribosomes. it transports proteins that were made on the attached ribosomes. large surface area

25
Q

what is the structure of SER

A

consists of a series of flattened membrane bound sacs called cisternae(same as RER but no ribosomes)

26
Q

what is the function of SER

A

synthesis, storage and transport of lipids and carbohydrates

27
Q

what is the function and structure of the flagellum

A

large extension of cell surface membrane containing microtubules able to beat to enable locomotion or move fluid

28
Q

what is the function and structure of the nucleus

A

contains the genetic material, controls the cell activities
the nuclear envelope separated the genetic material from the cytoplasm
nuclear pores allow molecules of mRNA to pass from the nucleus to the ribosomes in the cytoplasm
the nucleolus assembles the ribosomes

29
Q

what is the structure and function of lysosomes

A

small vacuoles containing hydrolytic enzymes

30
Q

what is the structure and function of the cytoskeleton

A

a network of microtubules and microfilaments, provides mechanical strength, maintains cell shape, movement of chromosomes, movement of cilia, changing shape of cell

31
Q

what is the function and structure of centrioles

A

involved in the organisation of the microtubules that make up the cytoskeleton
form the spindle fibres used to move chromosomes in nuclear division

32
Q

what is the structure of the cilia

A

small hair-like extension of the cell surface membrane containing microtubules
large numbers work in synchronised fashion

33
Q

what is the function of the cilia

A

able to move whole organism or to move fluid across a surface

34
Q

what are the characteristics of prokaryote

A

size: smaller - less than 10um long and 1-2um wide
nucleus: no
membrane - bound organelles: no
ribosomes: 70s
chromosomes: a single loop of DNA, no histones
flagellum: some cells

35
Q

what is the function of the chloroplast

A

site of photosynthesis

36
Q

what is the structure of the chloroplast

A

contains chlorophyll, granules lamellae( more in 5.1.2)

37
Q

what are the characteristics of a eukaryote

A

size: larger than 10um in diameter
nucleus: yes
membrane - bound organelles: yes
ribosomes: 80s
chromosomes: DNA associated with proteins(histones)
flagellum: some have a flagellum with 9+2 structure of microtubules

38
Q

what is the sequence of the production of proteins

A
  • mRNA leaves the nucleus via the nuclear pores
  • it is used by the ribosomes on the RER to construct a protein
  • the protein travels in a vesicle to the Golgi apparatus
  • the vesicles is moved by the cytoskeleton possibly using tiny protein motors that move along microtubules using them as a track
  • the Golgi apparatus modifies the protein (often adding a carbohydrate group) and repackages it into a vesicle
  • this vesicle is moved to the cell surface membrane
  • the vesicle fuses with the membrane to release the protein from the cell
    EXOCYTOSIS
39
Q

name 2 roles of the microtubules

A

microtubules can be prevented from functioning by a respiratory inhibitor
microtubules are involved in moving chromosomes from the equator to the poles of the cell during mitosis

40
Q

what is the description of an organelle which is not membrane bound

A

made of rRNA and protein

41
Q

what is found in both prokaryotes and eukaryotes

A

ribosomes

42
Q

what occurs in the nucleus of a cell

A

synthesis of RNA

43
Q

state what is meant by the resolution of a microscope

A

the ability to see more detail / separate two
objects

44
Q

what would be found in an immersed cell

A

sucrose solution

45
Q

state 3 statements that could be used as evidence for the endosymbiotic theory

A

mitochondria contain ribosomes that are smaller than those found in the cell cytoplasm
mitochondria are a similar size to bacteria
chloroplasts have their own circular DNA

46
Q

what are some things that onion root cells have and dont have

A

contains mitochondria
doesn’t contain chloroplast
doesn’t contain 70s ribosomes in cytoplasm
doesn’t have pili
has cellulose cell walls

47
Q
A

OCR AS/A Level Biology Context (24 decks)

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