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A-Level Biology > M2 C2 Cells > Flashcards

M2 C2 Cells Flashcards

1
Q

define magnification

A

the number of times greater an image is than the object

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2
Q

define resolution

A
  • the ability to distinguish between 2 points - the clarity of an image
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3
Q

what are the 3 main points of cell theory

A
  • both plant and animal tissue is composed of cells - cells are the basic unit of all life - cells only develop from existing cells
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4
Q

what is a photomicrograph

A

a photograph taken through a microscope

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5
Q

what energy source do ___ microscopes use

  1. optical/light
  2. laser scanning confocal
  3. Scanning electron microscope
  4. Transmission electron microscope
A
  1. light
  2. light
  3. electrons
  4. electrons
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6
Q

is a vacuum necessary for ___

  1. optical/light
  2. laser scanning confocal
  3. Scanning electron microscope
  4. Transmission electron microscope
A
  1. no
  2. no
  3. yes
  4. yes
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7
Q

what is ___ microscope used to view

  1. optical/light
  2. laser scanning confocal
  3. Scanning electron microscope
  4. Transmission electron microscope
A
  1. 2.
    3.
    4.
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8
Q

what resolution can be achieved by a ___ microscope

  1. optical/light
  2. laser scanning confocal
  3. Scanning electron microscope
  4. Transmission electron microscope
A
  1. 50-200 nm
  2. high- varies
  3. 3-10 nm
  4. 0.05-1.0 nm
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9
Q

explain the need for staining samples for use in light microscopes

A

many biological structures are colourless therefor stains are used to increase contrast in a specimen so that the components can become more visible & identified

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10
Q

how do you calculate magnification

A

magnification= image/actual

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11
Q

what are the advantages of using a ___ microscope

  1. optical/light
  2. laser scanning confocal
  3. Scanning electron microscope
  4. Transmission electron microscope
A
  1. relatively cheap, easy to use (portable). can study living specimens
  2. can focus on one focal plane at a time w/ a cell thus build up a 3D image
  3. v high magnification & resolution
  4. v high magnification & resolution
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12
Q

what are the disadvantages of using a ___ microscope

  1. optical/light
  2. laser scanning confocal
  3. Scanning electron microscope
  4. Transmission electron microscope
A
  1. long wavelength of light gives limited magnification due to low resolution
  2. lower resolution than EM, only see fluorescent objects which can cause artefacts
  3. v expensive requires high level of training, NOT able to view living material & artefacts are likely
  4. v expensive requires high level of training, NOT able to view living material & artefacts are likely
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13
Q

DESCRIBE THE STRUCTURE OF CHLOROPLAST [5]

A
  • A double membrane structure and contain a fluid called stroma
  • have an internal network of membranes which form flattened sacs called thylakoids
  • Several thylakoids stacked together form a granum which are joined by membranes called lamellae
  • The grana contain chlorophyll pigments
  • Chloroplasts contain DNA & ribosomes :. Can make proteins
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14
Q

WHAT IS THE FUNCTION OF CHLOROPLAST

A

To carry out photosynthesis

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15
Q

DESCRIBE THE STRUCTURE OF GOLGI [2]

A
  • Similar in structure to smooth endoplasmic reticulum

- Formed of cisternae, does NOT contain ribosomes

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16
Q

WHAT IS THE FUNCTION OF THE GOLGI APPARATUS? [3]

A
  • Modifies proteins and ‘packages’ them into vesicles
  • secretory vesicles, protein leaves cell
  • Lysosomes vesicles, protein stays in cell
17
Q

DESCRIBE THE STRUCTURE OF LYSOSOMES

A
  • Specialised forms of vesicles

- Contain hydrolytic enzymes

18
Q

WHAT IS THE FUNCTION OF THE LYSOSOMES ? [3]

A
  • Break down waste material in cells, including old organelles
  • Breaks down pathogens ingested by phagocytic cells
19
Q

DESCRIBE THE STRUCTURE OF MITOCHONDRIA [4]

A
  • Double membrane
  • Inner membrane highly folded to form cristae & fluid interior called matrix
  • Membrane contains enzymes for aerobic respiration
  • Contains small amount of DNA
20
Q

WHAT IS THE FUNCTION OF THE MITOCHONDRIA ?

A
  • Site for final stages of cellular respiration

- Stored energy is made available for cell by production of ATP

21
Q

DESCRIBE THE STRUCTURE OF A RIBOSOME

A
  • Not surrounded by a membrane
  • Constructed of RNA molecules
  • Found in mitochondria, chloroplast & attached to endop. reticulum to form RER
22
Q

WHAT IS THE FUNCTION OF THE RIBOSOME ?

A

site of protein synthesis

23
Q

DESCRIBE THE STRUCTURE OF THE NUCLEUS

A
  • Contains coded genetic info as DNA

- Contained within a double membrane (nuclear envelope) to protect it

24
Q

Describe the structure of a bacterial cell [11]

A
  • cell wall
  • cell membrane
  • ribosomes
  • plasmid
  • slime capsule
  • plasma membrane
  • nucleons region
  • flagella
  • pili
  • mesosome (site of respiration)
  • cytoplasm
25
Q

Describe the difference between DNA in eukaryote s and prokaryotes

A

Eukaryote- associated with histone proteins, contained within a nuclear envelope

Prokaryotes- naked, no proteins attached, free in nucleoid region in cytoplasm (plasmids are extra loop of dna in some prokaryotes)

26
Q

What are eukaryote and prokaryotic cell walls made from [2]

A

Prokaryotes-peptidoglycan

Eukaryotes- cellulose (plant cells only)

27
Q

Do prokaryotes/eukaryotes have a slime capsule

A

Pro- sometimes

Euk- no

28
Q

Do prokaryotes/eukaryotes have flagellum

A

Pro- sometimes, different strict. to eukaryotes

Euk- in some 9 & 2 microtubule structure

29
Q

Do prokaryotes/eukaryotes have ribosome

A

Pro- yes (smaller)

Euk- yes

30
Q

What are the 9 steps in protein synthesis

A
  1. mRNA copy of the gene for the protein is made
  2. mRNA leaves the nucleus through a nuclear pore
  3. mRNA attaches to ribosome ( on RER). Ribosome processes the code to assemble the correct protein
  4. Protein molecules are pinched of in vesicles and travel to Golgi
  5. Vesicles fuse with Golgi
  6. Golgi processes and packages protein molecules so they can be released
  7. Packaged protein molecules are pinched off in vesicles from Golgi and move towards plasma membrane
  8. Vesicles fuses w/ plasma membrane
  9. Plasma membrane opens to release protein (eg. insulin) outside cell
31
Q

What are microfilaments

A
  • made from the protein actin
  • retracts for whole cell movement
  • cell contracts for cell division
  • mechanical strength & support
32
Q

What are microtubules

A
  • made from protein Tubulin
  • forms scaffold to provide shape and structure
  • act as tracks for organelles to move
  • form spindle to make chromosomes in cell division
  • make up flagella, cilia and centrioles
33
Q

What are intermediate filaments

A
  • made from variety of proteins
  • anchors nucleus to cytoplasm
    Can attach cells to membrane basement

A-Level Biology (11 decks)

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