a2.2- cell structure Flashcards

1
Q

disadvantages of electron microscopy

A
  • specimen needs to die
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2
Q

advantages of electron microscopy [2]

A
  • higher range of magnification (can detect smaller structures)
  • higher resolution
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3
Q

why electron microscopy have higher resolution

A

shorter wavelength

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4
Q

freeze fracture

A

cut in half → spray metal
- see inside of membrane

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5
Q

cryogenic electron microscopy

A

see proteins with atomic precision- can design drugs that fit into them

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6
Q

florescent stains

A

bright colours- see it clearer

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7
Q

immunofluorescence

A

tag antibodies

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8
Q

structures common to calls in all living organisms [2]

A
  1. dna as genetic material
  2. cytoplasm enclosed by plasma membrane composed of lipids
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9
Q

use of plasma membrane

A

separating interior form its surrounding

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10
Q

functions of cytoskeleton [3]

A
  1. maintain cell shape
  2. organises cell parts
  3. enables cells to move and divide
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11
Q

components of cytoskeleton

A
  1. microtubules (movement)
  2. actin filaments (movement)
  3. intermediate filaments (structural)
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12
Q

process of life in unicellular organisms

A

metabolism
reproduction
homeostasis
growth
response to stimuli
excretion
nutrition

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13
Q

difference between eukaryotes (animals, plant and fungi)

A

see table

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14
Q

endosymbiotic theory

A
  • explains the existence of several organelles of eukaryotes
  • originated as symbioses between separate single-celled organisms
  • eukaryotic organisms engulfed by a prokaryotic cell, was not digested
  • remained inside host cell, carrying out aerobic respiration and providing energy to their host cells, evolving into mitochondria.
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15
Q

what does evidence suggest about eukaryotes

A
  • all eukaryotes evolved form common ancestor that had a nucleus and reproduced sexually
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16
Q

evidence of endosymbiotic theory [4]

A

MAD DRS
Membranes
- double membrane
- inner membrane has proteins similar to prokaryotes
Antibiotics
- susceptible to antibiotics (chloramphenicol)
- organelles may have bacterial origins
Division
- reproduction occurs via a fission-like process
- only through division of pre-existing mitochondria and chloroplasts
DNA
- own DNA: naked and circular
- like prokaryotic DNA structure
- transcribe their DNA
- use the mRNA to synthesise some of their own proteins
Ribosomes
- 70S
- similar to prokaryotes
Size
- similar size to bacteria

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17
Q

cell differentiation

A
  • development of a cell to carry out specific function
  • different patterns of gene expression: often triggered by changes in the environment
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18
Q

advantages to multicellularity

A
  1. larger body size
  2. cell specialisation
19
Q

polymer that forms part of cytoskeleton

A

tubulin

20
Q

doesnt conform to the idea of standard notions of a cell [5]

A
  1. striated muscle fibres
  2. aseptate fungal hyphae
  3. red blood cell
  4. phloem sieve tube
  5. giant algae
21
Q

striated muscle fibres

A

multiple nuclei surrounded by a single, continuous plasma membrane
challenges: cells always function as autonomous units

22
Q

asephate fungal hyphae

A

each aseptate hyphae is an uninterrupted tube-like structure with many nuclei spread along it

23
Q

red blood cell

A

no nucleus

24
Q

phloem sieve tube element

A
  • considered living cels without a nucleus
    nucleus of companion cells
  • controls their functional activities
25
Q

giant algae

A

may grow to very large sizes
challenges- larger organisms are always made of many microscopic cells

26
Q

why growing cells tend to divide and remain small

A

maintain high sa : vol ratio
- fast exchange of nutrients

27
Q

emergent properties

A
  • a property in which a collection or complex system had but the individual members do not have
  • interaction between parts produce more complex function than individually work together
    eg. grped cells → tissues, grped tissues → organs
28
Q

protista

A
  • eukaryote
  • uni/multi cellular
  • no specialised tissue
29
Q

fungi

A
  • cell wall made of chitin
  • obtain nutrition via heterotrophic absorption
30
Q

plantae

A
  • call wall made of cellulose
  • obtain nutrients autotrophically
31
Q

animalia

A
  • no cell wall
  • nutrition via heterotrophic ingestion
32
Q

factors that determine how a cell develops [4]

A
  1. position
  2. hormones
  3. cell to cell signals
  4. chemicals
33
Q

why is cell division necessary [5]

A
  1. more cells needed for growth
  2. replacement
  3. cells specialise
  4. cells have to divide when 5. they reach a certain size
    SA:vol ratio + nutrients cant be absorbed quickly enough
34
Q

nucleosome

A

DNA molecule wrapped around a core of eight histone proteins held together by an additional histone protein attached to linker DNA

35
Q

evidence that living organisms are composed of cells

A
  1. living organisms are multicellular
  2. organelles are specialised and contribute to the functions for the whole cell
  3. cells multiply through cellular division
36
Q

resolution definition

A

ability to differentiate two objects in a microscope, distinguishing the details of the specimen

37
Q

ultrastructure definition

A

structure of the cell as observed under the electron microscope

38
Q

formation of the nucleus

A

nucleoid region enclosed in the internal membrane- becomes the nucleus

39
Q

development of mitochondria

A
  1. aerobic proteobacterium enters a larger anaerobic prokaryote (as prey or parasite)
  2. survives digestion- becomes valuable endosymbiont
  3. aerobic proteobacterium provides rich source of ATP to its host- enables it to out-compete the other anaerobic prokaryotes
  4. host cell grows and divides so does the aerobic proteobacterium
  5. subsequent generations- contain aerobic proteobacterium
  6. aerobic proteobacterium
    evolves and is assimilated to become a mitochondrion
40
Q

advantages of cell differentiation [2]

A
  1. helps the body to carry out very specific functions efficiently
  2. helps the organisms acquire specialisation for survival
41
Q

in which type of cells is the entire genome active

A

embryotic cell

42
Q

how newly formed cells become specialised

A

transcription regulators
- some genes turned on or off
- depends on the specialisation and location of cell during embryotic stage

43
Q

organelles both prokaryotes and eukaryotes have [4]

A
  1. cell membrane
  2. cytoplasm
  3. ribosomes
  4. genetic material