cell structure and organisation Flashcards

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1
Q

mitochondria structure

A
  • 5um long
  • 2 membranes
  • fluid filled intermembrane space, folded inwards = cristae
  • circle of DNA
  • matrix contains lipids, proteins, enzymes
  • 70s ribosomes
  • large SA:V
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2
Q

mitochondria function

A
  • ribosomes for protein synthesis
  • DNA allows replication
  • produces ATP for aerobic respiration
  • enzymes for respiration
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3
Q

ribosomes strucutre

A
  • 70s = prokaryote, 80s = eukaryote
  • 1 large, 1 small subunit
  • assembled in nucleolus from rRNA and protein
  • pass out into cytoplasm
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4
Q

ribosomes function

A
  • site of protein synthesis
  • read mRNA sequence
  • translate genetic code into amino acids which fold into proteins
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5
Q

golgi body strucutre

A
  • fluid filled, flattened sacs
  • surrounded by vesicles
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6
Q

features of mitochondria and their significance

A
  • looped DNA = codes for essential proteins in respiration
  • 70s ribosomes = translate DNA to produce proteins
  • cristae (infoldings) = increase SA of inner membrane
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7
Q

golgi body function

A
  • modify, process, package proteins
  • transport and store lipids
  • produce secretory enzymes, e.g. lysosome
  • secrete carbohydrase for plant cell walls
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8
Q

lysosome structure

A
  • small, temporary vesicles
  • single membrane
  • contain digestive enzymes
  • pinch off golgi body
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9
Q

lysosome function

A
  • digestive enzymes breakdown / recycle cellular waste and unwanted material
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10
Q

nucleolus structure

A
  • spherical structure
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11
Q

nucleolus function

A
  • produces and assembles ribosomes
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12
Q

nucleus structure

A
  • double membrane form nuclear envelope
  • pores allow large molecules to leave (mRNA, ribosomes)
  • contains DNA
  • contains nucleoplasm
  • contains nucleolus
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13
Q

what is nucleoplasm?

A
  • granular material in the nucleus
  • contains chromatin (coils of DNA)
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14
Q

nucleus function

A
  • controls and regulates activities of the cell
  • contains cells genetic material
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15
Q

chromatin structure

A
  • chain of nucleosomes
  • coils of DNA that condense into chromosomes
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16
Q

chromatin function

A
  • package DNA into the tight/small space of the nucleus
  • condense into chromosomes during cell division
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17
Q

plasmodesmata structure

A
  • fine strands of cytoplasm
  • extend through pores in plant cell walls
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18
Q

plasmodesmata function

A
  • facilitate movement of molecules between cells
  • allow communication between cells
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19
Q

endoplasmic reticulum strucutre

A
  • double membrane
  • flattened sacs with fluid filled spaces (the cristernae)
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20
Q

rough er structure

A
  • series of flattened sacs enclosed by a membrane
  • ribosomes on the surface
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21
Q

rough er function

A
  • folds and processes proteins
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22
Q

smooth er structure

A
  • system of membrane bound sacs that lack ribosomes
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23
Q

smooth er function

A
  • synthesis and transport of lipids
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24
Q

centrioles strucutre

A
  • hollow cylinders
  • rings of microtubules
  • in animals and plant cells (absent in higher plants)
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25
Q

centrioles function

A
  • organise microtubules that make spindle fibres in cell division
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26
Q

chloroplasts structure

A
  • 2 membranes form chloroplast envelope
  • fluid filled stroma contains photosynthesis products
  • 70s ribosomes
  • circular DNA
  • chlorophyll found on flattened sacs, thylakoids
  • stacks of thylakoids = grana
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27
Q

chloroplast function

A
  • can make proteins and self replicate
  • contains photosynthetic pigment to capture sunlight and convert into energy
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28
Q

vacuole structure

A
  • large, permanent fluid filled sac
  • bound by single membrane = tonoplast
  • sap stores nutrients, water, chemicals
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29
Q

vacuole function

A
  • maintains pressure in plant cells
  • supports plant cell walls
  • prevents wilting
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30
Q

nuclear envelope strucutre

A
  • double membrane of the nucleus
31
Q

nuclear envelope function

A
  • prevents genetic material mixing with cytoplasm
32
Q

RER vs SER

A
  • RER has ribosomes on outer surface (SER doesn’t)
  • RER facilitates protein synthesis (SER synthesises lipids)
  • RER provides transport (SER provides storage and transport)
33
Q

chloroplast adaptations for photosynthesis

A
  • granal membrane = large SA
  • fluid in stroma contains enzymes and sugars
  • chloroplasts have DNA and ribosomes for rapid protein synthesis
34
Q

how are organelles interrelated?

A
  • nucleus contains chromosomes where DNA encodes proteins
  • nuclear pores in nuclear envelope allow mRNA to leave nucleus and attach to ribosomes
  • ribosomes contain rRNA transcribed from DNA in nucleolus
  • protein synthesis occurs on ribosomes
  • polypeptides made on ribosomes move through RER and pack into vesicles that bud of the golgi body
  • golgi body produces vesicles containing proteins
  • phospholipids and triglycerides move through SER
35
Q

organelle definition

A
  • specialised structure with a specific function inside a cell
  • work together to carry out functions
36
Q

eukaryotic definition

A
  • distinct nucleus
  • membrane bound organelles
  • animal or plant cells
  • 80s ribosomes
  • large SA for enzymes
37
Q

prokaryotic definition

A
  • single celled
  • lack membrane bound organelles
  • DNA free in cytoplasm
  • reproduce by binary fission
  • all life functions in 1 cell
  • no mitochondria or nucleus
38
Q

plant cell wall structure

A
  • cellulose held together into fibres embedded in a matrix
39
Q

plant cell wall function

A
  • transport: gaps between fibres = permeable to water and dissolved substances.
  • mechanical strength: cellulose microfibres are strong and resist expansion
  • communication: pores allow strands of cytoplasm (plasmodesmata) to pass, creating the symplast pathway
40
Q

prokaryotes strucutre

A
  • 70s ribosomes
  • cytoplasm
  • cell membrane
  • cell wall
  • DNA in nucleoid region
  • small
  • single celled
41
Q

cell wall in bacteria (prokaryote)

A
  • rigid outer covering
  • made of peptidoglycan
42
Q

capsule in bacteria (prokaryote)

A
  • protective slimy layer
  • retains moisture
  • allows organism to adhere to other surfaces
43
Q

plasmid in bacteria (prokaryote)

A
  • circular piece of DNA
44
Q

flagellum in bacteria (prokaryote)

A
  • tail like structure
  • rotates to move cell
45
Q

pili in bacteria (prokaryote)

A
  • hair like structure
  • attract other bacterial cells / adhere
46
Q

mesosomes in bacteria (prokaryote)

A
  • infoldings of inner membrane
  • contains enzymes for respiration
  • increase SA
47
Q

what is a virus?

A

non-living microorganism
consists of nucleic acid enclosed in a protective protein husk (capsid)
lipid layer forms an envelope
- acellular

48
Q

what do viruses do?

A

invade cells
take over cells metabolism
use host cells machinery to replicate

49
Q

structure of a virus

A
  • core of nucleic acid (DNA/RNA)
  • surrounded by a protein coat, CAPSID (coded by viral genes)
50
Q

what is the cell theory

A
  • new cells are formed from other existing cells
  • cells are the fundamental unit for life (structure, function, organisation of living organisms)
  • cells contain genetic material transferred to daughter cells
51
Q

levels of organisation

A
  • groups of cells with a shared specific function are arranged into tissues
  • several types of tissues combine to from an organ
  • multiple organs come together to form an organ systems
  • organ systems make up an organism
52
Q

differentiation definition

A

development of a cell into a specific type
becoming specialised in structure and reactions

53
Q

tissue definition

A

group of cells working together with a common function, structure and origin

54
Q

organ definition

A

several tissues in a structural unit
work together to form a specific function

55
Q

organ system definition

A

group of organs
work together with a particular role

56
Q

organism definition

A

all bodily systems working together
forming a discrete individual

57
Q

what is epithelial tissue?

A
  • continuous layer lining internal and external surfaces
  • no blood vessels
  • some have nerve endings
  • sit on a basement membrane
  • protective or sensory function
58
Q

types of epithelial tissues

A
  • simple cuboidal
  • columnar
  • squamous
59
Q

what is simple cuboidal epithelial tissue?

A
  • cube shaped
  • 1 cell thick
  • in PCT and salivary glands
  • can be ciliated
60
Q

what is columnar epithelial tissue?

A
  • elongated cells
  • line tubes (e.g. trachea,oviduct) allowing substances through
  • may have cilia
61
Q

what is squamous epithelial tissue?

A
  • flattened cells on basement membrane
  • form walls of alveoli
  • line Bowman’s capsule
62
Q

what are ciliated epithelial?

A
  • contain goblet cells
  • secrete mucus
  • move harmful particles out the body
63
Q

types of muscle tissue

A
  • skeletal (striated)
  • smooth
  • cardiac
64
Q

what is skeletal muscle tissue?

A
  • generates movement
  • bands of long fibres
  • produce powerful, voluntary contractions
  • tire easily
  • striped / striated
65
Q

what is smooth muscle tissue?

A
  • individual spindle shaped cells
  • contract rhythmically
  • in skin
  • in blood vessel walls
  • involuntary contractions
  • weaker
66
Q

what is cardiac muscle tissue?

A
  • only in the heart
  • striped cells but lack long fibres (of skeletal)
  • contract rhythmically without nerve/hormone stimulation
  • contractions can be modified
  • don’t tire
67
Q

what is connective tissue?

A
  • connects, supports or separates tissues and organs
  • elastic and collagen fibres
  • e.g. bones, tendon, blood cell
68
Q

adaptions of epithelial cells

A
  • microvilli; increase SA for absorption of nutrients
  • thin; decreases diffusion distance for gas exchange
  • ciliated; moves mucus out of breathing system
69
Q

capsule vs capsid

A
  • capsid: outer protective layer of a virus
  • capsule: outer protective layer of bacteria
70
Q

structure of human cell vs virus (3)

A
  • humans genetic material is DNA, virus only has RNA
  • human cell has cell membrane, virus has capsid
  • human cell has nucleus, virus doesn’t
  • human cell has membrane bound organelles, virus has no organelles
  • human cell has chromosomes, viruses don’t
71
Q

how is viral RNA replicated? (3)

A
  • RNA released from virus capsid inside host cell
  • RNA polymerase reads base sequence on virus RNA
  • free RNA nucleotides pair with nucleotides on virus RNA
  • complementary base pairing
  • RNA polymerase catalyses formation of RNA molecule
72
Q

how is viral RNA used to make viral protein molecules? (3)

A
  • replicated viral RNA attaches to ribosome
  • tRNA matches anticodon to codons on viral RNA
  • complementary base paring
  • tRNA brings amino acids to ribosome
  • amino acids joining by peptide bonds = polypeptide
73
Q

why is a virus not considered to be a cell?

A

it is acellular
it has no membrane bound organelles