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

Chapter 2 - Basic Components of Living Systems Flashcards

(53 cards)

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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

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

function of plasma membrane

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

the process of protein production

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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
define magnification
how many times bigger the image produced by the microscope is than the actual size of the object
26
define resolution
the ability to see two objects that are close together as seprate entities
27
what is the cytoskeleton
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
3 components of cytoskeleton
- microfilaments - microtublules - intermediate fibres
29
microfilaments
- made of actin (protein) - responsible for cell movement - and cell contraction in cytokenisis - act as a skeleton and support the cell
30
microtubules
- determine shape of cell - act as tracks for organelle movement - spindle fibres are made of microtubules - 9+2 formation
31
intermediate fibres
- mechanical strength and help cells maintain integrity
32
differences between prokaryotes and eukaryotes
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
why do some cells need to be stained
stains provide contrast to make cells or organelles visible and allow them to be distinguished from others
34
what is methylene blue used for
all purpose stain, turns cells blue
35
what is phloroglucinol used for
staining cells red/ pink
36
what does acetic orcein bind to and its colour
binds to DNA, staining chromosomes dark red
37
what allowed certain parts of cells to be stained
certain tissues absorb certain dyes depending on their chemical nature
38
magnification and resolution of light microscope
2000x 200nm
39
magnification and resolution of laser scanning microscope
2000x difficult to determine
40
magnification and resolution of transmission electron microscope
500,000x 0.2nm
41
magnification and resolution of scanning electron microscope
100,000x 0.2nm
42
function of light microscope
using visible light to illuminate a thin section of a sample
43
function of laser scanning microscope
- looking at thin sections of a sample - looking at parts of the cell by labelling with fluorescence
44
function of transmission electron microscope
- looking at very thin cross-sections of an object such as a cell
45
function of scanning electron microscope
- looking at the surface of objects at a high resolution
46
advantages of light microscopes
- look at living cells - looking at cells and tissues
47
advantages of laser scanning microscopes
- look at living cells - highlighting individual components of cells
48
advantages of transmission electron microscopes
- looking at internal structures - high resolution
49
advantages of scanning electron microscopes
- looking at surfaces of objects - provides a 3D image
50
disadvantages of light microscopes
low resolution compared to electron microscopes
51
disadvantages of laser scanning microscopes
- low resolution compared to light microscopes - only see fluorescent objects - fluorescence causes artefacts
52
disadvantages of transmission electron microscopes
- cant observe living things - expensive
53
disadvantages of scanning electron microscopes
- not as high resolution and magnification as TEM - cant observe living things - expensive
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