[3.4] structure of eukaryotic cells Flashcards

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1
Q

what is the function of mitochondria?

A

aerobic respiration

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2
Q

what are the key features of mitochondria? (7)

A
  1. outer mitochondrial membrane
  2. inner mitochondrial membrane
  3. inter-membrane space
  4. mitochondria DNA
  5. ribosomes
  6. cristae
  7. mitochondrial matrix
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3
Q

what is mitochondrial DNA?

A
  • allows mitochondria to be self-sustaining and means they are prokaryotes,
  • is the genetic material giving instructions for which proteins to make all the ribosomes
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4
Q

what are ribosomes?

A
  • it is where protein synthesis occurs
  • produces key respiratory enzymes in mitochondria
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5
Q

what are cristae?

A
  • infoldings of the inner membrane to increase SA
  • where ATP is produced
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6
Q

what is in the mitochondrial matrix?

A

key respiratory enzymes

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7
Q

what are the key features of chloroplasts? (8)

A

1.double membrane
2. ribosomes
3. thylakoid
4. granum
5. inter-granal lamella
6. stroma
7. DNA
8. starch grains

[drawing] (https://www.google.com/url?sa=i&url=https%3A%2F%2Fzhtutorials.com%2F2020%2F10%2F07%2Fchloroplasts%2F&psig=AOvVaw2KXlDN3ZDNIS1MXR4xsXrR&ust=1713475596724000&source=images&cd=vfe&opi=89978449&ved=0CBIQjRxqFwoTCLDmhZaYyoUDFQAAAAAdAAAAABAR)

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8
Q

what is the function of the double membrane in chloroplasts?

A
  • it is selectively permeable
  • it has proteins that determines what can enter
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9
Q

what is the function of the thylakoid?

A
  • it is where the 1st stage of photosynthesis occurs: light absorption by chlorophyll (light dependent stage)

small, pancake-like discs

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10
Q

what is the function of the granum?

A

to increases surface area cumilatively

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11
Q

what is the inter-granal lamella?

A

it is a thin rod between grana that connects them

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12
Q

what is the function of the stroma?

A
  • where key enzymes for photosynthesis are found
  • where 2nd stage of photosynthesis occurs: glucose production (light independent stage)

(like cytoplasm if it were a cell)

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13
Q

key features of the nucleus (5)

A
  1. nucleoplasm
  2. chromosome
  3. nuclear envelope (double membrane)
  4. nuclear pore
  5. nucleolus
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14
Q

what does the chromosome in a nucleus contain?

A

DNA wrapped around beads of ‘histone’ protein

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15
Q

what is the function of the nuclear pore?

A

enables entry and exit of:

  • mRNA
  • tRNA
  • rRNA
  • proteins
  • ribosomes
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16
Q

what is the function of the nucleolus?

A
  • produces rRNA
  • assembles ribosomes
17
Q

what are the functions of the nucleus? (textbook)

A
  • to act as control centre of cell by producing mRNA and tRNA and hence protein synthesis
  • to store the genetic material of the cell in the form of DNA and chromosomes
  • make rRNA and ribosomes
18
Q

key features of the ribosome (4)

A
  1. small ribosomal subunit
  2. large ribosomal subunit
  3. ribosomal grooves (where mRNA binds)
  4. binding sites (for tRNA and associated amino acids)
19
Q

what are ribsomes made of and what size are they?

A
  • prokaryote = smaller (70s)
  • eukaryote = larger (80s)
  • ribosomes are made of protein and rRNA
20
Q

what is the endoplasmic reticulum?

A

an extensive network of flattened interconnected tubes within the cytoplasm

21
Q

rough ER

A
  • has ribosomes embedded on the surface of the membrane
  • used to store and transport proteins
  • sometimes found close to nucleus
22
Q

smooth ER

A
  • no ribosomes
  • used to store and transport lipids and carbohydrates
23
Q

key features of golgi apparatus (2)

close to RER

A
  • cisternae (membrane stacks)
  • golgi vesicles
24
Q

what are golgi vesicles?

A

small membrane bound sacs that ‘bud off’ from the main membranes due to membrane fluidity

25
Q

what is the role of the golgi apparatus? (class)

A
  1. modifying proteins
    - folding & coiling into a specific 3D shape
    - addition of non protein components eg. Fe for haemoglobin
  2. packaging proteins
    - adding ‘finalised’ protein into golgi vesicles to be transported elsewhere in/out of cell
26
Q

what are the functions of the golgi apparatus? (textbook)

A
  • add carbohydrate to proteins to form glycoproteins
  • produce secretory enzymes, such as those secreted by the pancreas
  • secrete carbohydrates, such as those used in making cells walls in plants
  • transport, modify, and store lipids
  • form lysosomes
27
Q

what is the importance of membrane fluidity/where is it used?

A
  • meiosis
  • mitosis
  • phagocytosis
28
Q

key features of lysosome (2)

(example of a vesicle)

A
  • membrane: keeps enzymes tucked away until they are needed
  • lysozymes: powerful hydrolytic enzymes that are used in digestion
29
Q

what are lysosomes used for? (class)

A
  1. phagocytosis: to hydrolyse pathogens
  2. apoptosis: programmed (intentional) cell death for unwanted or damaged cells
30
Q

what are the functions of lysosomes? (textbook)

A
  • hydrolyse material ingested by phagocytic cells, such as white blood cells and bacteria
  • release enzymes to the outside of the cell (exocytosis) in order to destroy material around the cell
  • digest worn out organelles so that the useful chemicals they are made of can be re-used
  • completely break down cells after they have died (autolysis)
31
Q

key features of the vacuole (2)

A
  • cell sap
    > mostly water with dissolved sugars (eg. monosaccharides) and dissolved mineral ions
  • tonoplast (vacuole membrane)
32
Q

what is the role of the vacuole? (class)

A
  1. storage of the sap
  2. structural role: full vacuole exerts pressure (‘turgidity’) outwards on the cell wall so the shape of the cell is maintained
33
Q

what are the functions of the vacuole? (textbook)

A
  • support herbaceous plants, and herbaceous parts of woody plants, by making cells turgid
  • the sugars and amino acids may act as a temporary food store
  • the pigments may colour petals to attract pollinating insects
34
Q

what is the cell wall made of?

A
  • cellulose fibrils
  • microfibrils bundled together into macrofibrils that form a mesh-like network

> made of multiple straight chains of beta glucose molecules

35
Q

3 versions of cell wall + vacuole

A
  • turgid (normal) - when no more water can physically enter the cell as vacuole swells and presses cytoplasm against cell wall during osmosis
  • flaccid (soft) - when cells are no longer firm and swollen as solution surrounding plant cells is hypertonic so water will leave
  • plasmolysed - when too much water is lost by osmosis so the vacuole and cytoplasm shrink, and eventually the cell membrane pulls away from the cell wall
36
Q

properties of the cell wall (how and why)

A
  • the cell wall is strong and rigid
  • this is so it is able to resist turgor pressure of the vacuole and maintain the cell shape
  • it is strong and rigid due to long, straight, unbranched chains which have hydrogen bonds between chains
37
Q

what are the functions of the cell wall? (textbook)

A
  • to provide mechanical strength in order to prevent the cell bursting under the pressure created by the osmotic entry of water
  • to give mechanical strength to the plant as a whole
  • to allow water to pass along it and so contribute to the movement of water through the plant