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A-level Biology > Chapter 2 - Basic Components of Living Systems > Flashcards

Chapter 2 - Basic Components of Living Systems Flashcards

1
Q

Function of the nucleus

A
  • contains genetic information as DNA stored as chromatin
  • DNA controls protein synthesis, the cells metabolic activity, growth and reproduction
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2
Q

structure of the nucleus

A
  • contained by nuclear envelope (double membrane) to protect from damage from cytoplasm
  • nuclear pores control entry and exit of molecules from nucleus eg. mRNA
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3
Q

function of nucleolus

A
  • produces ribosomes from proteins and rRNA
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4
Q

structure of nucleolus

A
  • made of proteins and RNA (which is used to produce rRNA)
  • in nucleus, not surrounded by a membrane
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5
Q

function of mitochondria

A
  • site of cellular aerobic respiration and ATP production
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6
Q

structure of mitochondria

A
  • double membrane
  • inner membrane folds: cristae has high surface area
  • matrix has enzymes for aerobic respiration
  • circular DNA
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7
Q

function and structure of vesicles

A
  • membranous sacs, single membrane with fluid inside
  • used to transport materials inside the cell
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8
Q

function and structure of lysosomes

A
  • specialised vesicles (single membrane)
  • contain hydrolysing enzymes that digest organelles, cells and pathogens
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9
Q

structure and function of centrioles

A
  • formation of spindle fibres
  • crucial in spatial awareness of cell
  • part of the cytoskeleton, made of microtubules
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10
Q

where are centrioles found

A

animal cells and some plant (except flowering plants) absent from most fungi

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11
Q

structure and function of cilia

A
  • mobile/ stationary with microtubules arranged in 9+2 formation
  • stationary: sensory function eg. in nose
  • mobile: beat rhythmically to create a current
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12
Q

structure and function of flagella

A
  • enables cells to be motile
  • sometimes a sensory organelle used to detect environmental changes
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13
Q

structure and function of RER

A
  • synthesis and transport of proteins
  • a series of membranes continuous with nuclear envelope
    enclosing flattened sacs: called cisternae
  • Ribosomes on surface
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14
Q

function and structure of smooth ER

A
  • synthesis, transport and storage of lipids, carbohydrates and steroid hormones
  • series of membranes not continuous with nuclear membrane, but with RER
  • cisternae
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15
Q

strucure and function of ribosomes

A
  • made of RNA molecules from nucleolus
  • site of protein synthesis
  • can be in cytoplasm or on RER
  • also in mitochondria and chloroplasts
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16
Q

structure and function of Golgi apparatus

A
  • stack of membrane-bound flattened sacs (cisternae)
  • modify proteins + lipids (e.g. add sugar to make glycoproteins)
  • and package into vesicles
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17
Q

different materials of cell wall

A

plant: cellulose
prokaryote: peptidoglycan
fungi: chitin

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18
Q

function of cell wall

A
  • plants: provide shape, contents presses against it creating rigidity (turgor pressure), tensile strength
  • prokaryotes: maintain shape
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19
Q

structure and function of permenant vacuole

A
  • surrounded by single membrane tonoplast
  • maintains turgor pressure to maintain rigid framework
  • contains nutrients and metabolites
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20
Q

function of chloroplasts

A

chlorophyll in grana, where light dependent reactions occur during photosynthesis

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21
Q

structure of chloroplasts

A
  • stacks of double membranes containing photosynthetic pigments
  • stacks: grana, membranes: thylakoids
  • fluid inside: stroma
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22
Q

function of cytoplasm

A
  • medium for organelle suspension
  • site of some chemical reactions
  • buffer to protect cell contents from damage
23
Q

function of plasma membrane

A
  • surrounds the cell, controls the entry and exit of substances
  • detects and responds to environmental changes
24
Q

the process of protein production

A
  • mRNA made in nucleus (transcription)
  • mRNA leaves nucleus through pore and attaches to ribosome.
  • Ribosome assembles protein (translation)
  • Protein travels in vesicle which fuses with Golgi apparatus (cis-face)
  • Golgi apparatus modifies and packages protein.
  • Protein travels to and fuses with plasma membrane in a vesicle.
  • Plasma membrane opens up to release protein (exocytosis)
25
Q

define magnification

A

how many times bigger the image produced by the microscope is than the actual size of the object

26
Q

define resolution

A

the ability to see two objects that are close together as seprate entities

27
Q

what is the cytoskeleton

A

in cytoplasm of all eukaryotic cells:
- network of fibres necessary for shape and stability of cell
- holds organelles in place
- controls cell and organelle movement

28
Q

3 components of cytoskeleton

A
  • microfilaments
  • microtublules
  • intermediate fibres
29
Q

microfilaments

A
  • made of actin (protein)
  • responsible for cell movement
  • and cell contraction in cytokenisis
  • act as a skeleton and support the cell
30
Q

microtubules

A
  • determine shape of cell
  • act as tracks for organelle movement
  • spindle fibres are made of microtubules
  • 9+2 formation
31
Q

intermediate fibres

A
  • mechanical strength and help cells maintain integrity
32
Q

differences between prokaryotes and eukaryotes

A

Prokaryotes: no nucleus
- 70s ribosomes not 80s (smaller)
-no centrioles
-no membrane-bound organelles
- different cell wall (peptidoglycan or chitin)
-circular DNA free in cytoplasm
-plasmids
-flagella no 9+2 formation of microtubules

33
Q

why do some cells need to be stained

A

stains provide contrast to make cells or organelles visible and allow them to be distinguished from others

34
Q

what is methylene blue used for

A

all purpose stain, turns cells blue

35
Q

what is phloroglucinol used for

A

staining cells red/ pink

36
Q

what does acetic orcein bind to and its colour

A

binds to DNA, staining chromosomes dark red

37
Q

what allowed certain parts of cells to be stained

A

certain tissues absorb certain dyes depending on their chemical nature

38
Q

magnification and resolution of light microscope

A

2000x
200nm

39
Q

magnification and resolution of laser scanning microscope

A

2000x
difficult to determine

40
Q

magnification and resolution of transmission electron microscope

A

500,000x
0.2nm

41
Q

magnification and resolution of scanning electron microscope

A

100,000x
0.2nm

42
Q

function of light microscope

A

using visible light to illuminate a thin section of a sample

43
Q

function of laser scanning microscope

A
  • looking at thin sections of a sample
  • looking at parts of the cell by labelling with fluorescence
44
Q

function of transmission electron microscope

A
  • looking at very thin cross-sections of an object such as a cell
45
Q

function of scanning electron microscope

A
  • looking at the surface of objects at a high resolution
46
Q

advantages of light microscopes

A
  • look at living cells
  • looking at cells and tissues
47
Q

advantages of laser scanning microscopes

A
  • look at living cells
  • highlighting individual components of cells
48
Q

advantages of transmission electron microscopes

A
  • looking at internal structures
  • high resolution
49
Q

advantages of scanning electron microscopes

A
  • looking at surfaces of objects
  • provides a 3D image
50
Q

disadvantages of light microscopes

A

low resolution compared to electron microscopes

51
Q

disadvantages of laser scanning microscopes

A
  • low resolution compared to light microscopes
  • only see fluorescent objects
  • fluorescence causes artefacts
52
Q

disadvantages of transmission electron microscopes

A
  • cant observe living things
  • expensive
53
Q

disadvantages of scanning electron microscopes

A
  • not as high resolution and magnification as TEM
  • cant observe living things
  • expensive

A-level Biology (16 decks)

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