Cell Biology Flashcards

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1
Q

What is the cell membrane made out of, and which way does each component face?

A
  • double layer of phospholipids

- polar head faces outwards towards water, and non-polar tails face each other at the centre of the membrane

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2
Q

What are other molecules embedded inside the cell membrane used for?

A

Transport, recognition, etc.

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3
Q

The cell membrane is s____ p____. What does that mean?

A
  • selectively permeable

- certain molecules can pass through, while others cannot

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4
Q

Three types of passive transport

A

Diffusion, osmosis, and facilitated diffusion

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5
Q

What is passive transport?

A
  • A process that does not require energy from the cell
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6
Q

What is diffusion?

A
  • It is the natural movement of particles from areas of high concentration, two areas of low concentration
  • cell membrane can’t prevent passive transport if it is permeable to a substance (oxygen, CO2, lipid soluble molecules)
  • Moving down or following the concentration gradient
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7
Q

What is the concentration gradient?

A
  • The gradient is a difference in a quality between two adjacent regions
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8
Q

What is osmosis?

A
  • osmosis is the diffusion of water (solvent) across a semi-permeable membrane
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9
Q

Describe when a cell is isotonic to surround fluid

A
  • if [water] outside cell = [water] inside cell

- water movement in and out are equal

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10
Q

Describe when the cell is hypertonic to surrounding fluid

A

If [water] outside cell > [water] inside cell

  • water moves into cell
  • freshwater extracellular fluid is hypotonic
  • cell swells and possibly bursts
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11
Q

Describe when a cell is hypotonic to surrounding fluid

A

If [water] inside cell > [water] outside cell

  • water moves out of cell
  • salty extracellular fluid is hypertonic
  • cell shrinks as water moves out
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12
Q

Which direction does water move towards in osmosis?

A
  • water moves towards a hypertonic solution until an equilibrium is reached
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13
Q

Describe facilitated diffusion

A
  • passive transport
  • movement of particles across the membrane, down the concentration gradient
  • aided by a membrane protein
    Ex. Glucose and other carbohydrates as too large for simple diffusion through the membrane
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14
Q

What is special about membrane proteins?

A
  • they are very selective based upon shape, size, and electrical charge
  • they only help a certain molecule through the membrane
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15
Q

Two types of membrane proteins that help in transport

A

Carrier proteins and channel proteins

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16
Q

What are channel proteins?

A
  • tunnel-shaped protein through cell membrane
  • have a charge
  • positive channel specific for negative ion or molecule to pass
  • negative channel specific for positive ion or molecule to pass
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17
Q

Types of proteins embedded in the phospholipids of cell membranes

A
  • receptor proteins
  • transport proteins (carrier and channel)
  • Recognition protein
  • enzymatic protein
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18
Q

Receptor proteins

A
  • has a specific site that allows a specific molecule to bind to it
  • A chemical messenger or hormone must fit the receptor site in order to affect the metabolism of the target cell
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19
Q

Carrier protein

A
  • has a specific shaped site(s) of attachment

- combines with a molecule like glucose, or ions like Na+ and k+ and moves them across the membrane

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20
Q

Recognition protein

A
  • has a specific carbohydrate chain attached to it
  • chain is different for each person
  • identifies that the cell belongs in your body
  • your immune system under normal circumstances will only attack a foreign invaders such as a virus, or cells that aren’t yours
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21
Q

Enzymatic proteins

A
  • when activated, it causes a reaction to occur that will affect the metabolism of the cell
  • reaction occurs on the cytoplasm side of the proteins in the cytoplasm
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22
Q

Fluid mosaic model

A
  • what scientist believe the cell membrane looks and functions like
  • based on the changing location (fluid) and patterns of proteins (mosaic) in the phospholipid layer
23
Q

What is active transport?

A
  • uses energy to allow cells to transport molecules and larger particles across the membrane
  • Active transport is against the concentration gradient
  • ATP molecules used in the process
  • ATP splitting to a phosphate ion and ADP releases energy to be used for transport
24
Q

Sodium potassium pump

A
  • uses energy of ATP to transport
    sodium ions out of the cell and potassium ions into the cell
  • carrier protein changes shape
  • exchanges three sodium ions for two potassium ions, so excess positive charge outside cell
  • pumps force molecules or ions to move from areas of low concentration to high concentration (against CG)
25
Q

Three types of cell transport

A

Passive transport, Active transport, bulk transport

26
Q

What is bulk transport and what are the forms of it?

A
  • requires vesicles and metabolic energy

- Endocytosis, pinocytosis, receptor-mediated endocytosis, and exocytosis

27
Q

How does endocytosis work?

A
  • The cell membrane folds inward, engulfing macromolecules and other large particles into a cell
  • A membrane-bound vesicle results, containing the particle
  • requires energy input in the form of ATP
28
Q

Three methods of endocytosis

A

Phagocytosis , pinocytosis, receptor-mediated endocytosis

29
Q

Phagocytosis

A
  • cell eating
  • cell wants to taking large particles specific to it (macromolecules and bacteria)
  • might be when a cell is trying to eat up a larger cell
30
Q

What is pinocytosis?

A
  • cell drinking
  • cell is pulling inward inclusion, which then sucks in liquids and solutes and pinches off (extracellular fluid)
  • occurs for all cell types
31
Q

Receptor- mediated endocytocis

A
  • cell is choosing to take in specific molecules
  • inclusion coming in, wrapped in proteins
  • each protein is waiting for the right type of particle to bind to it
  • cell pinches and closes
  • cell is targeting what it wants to bring in
32
Q

What is exocytosis?

A
  • A membrane bound vesicle containing enzymes, wastes, or hormones, attaches to the plasma membrane and releases its contents to the exterior
  • The vehicle membrane becomes part of the plasma membrane
  • requires the input of energy in the form of ATP
33
Q

What is the lysosome function?

A
  • vesicle containing digestive enzymes (breaking down)

- contain completed “ready” enzymes

34
Q

Process of creating lysosomes

A
  • rough ER produces enzymes (proteins)
  • enclosed within vesicles in the Golgi apparatus to process the proteins
  • proteins turn into lysosomes
    Please see handout
35
Q

Smooth/Rough ER and Golgi body relationship

Or

How are proteins transported out of the cell?

A
  1. Ribosomes (build proteins) sequence amino acids into proteins in the rough ER
  2. Proteins first enter rough ER, and move into smooth ER
  3. Smooth ER produces vacuoles that transport protein to Golgi body
  4. Vacuoles are incorporated into the Golgi, where they are processed and packaged
  5. Substances are combined and released by the Golgi as secretory vesicles
  6. Vesicles make their way to the cell membrane and release their contents (digestive enzymes released by intestinal cells, signalling molecules released from one cell to another) AKA EXOCYTOSIS
36
Q

Process of proteins transported out of cell dumbed down

A
  • Ribosomes on rough ER produces proteins
  • move into smooth the ER
  • smooth ER produces vacuoles the transport protein to Golgi
  • processing and packaging in the Golgi, released by Golgi as secretory vesicles
  • vesicles make a way to cell membrane and exocytosis occurs
37
Q

Process of photosynthesis

A
  • chloroplast convert solar energy into chemical energy, and stored It as sugars
  • produces oxygen and ATP that is immediately stored in sugar
38
Q

Which organisms carry out photosynthesis, and what can they do?

A
  • autotrophs

- organisms that can make their own food

39
Q

What is the photosynthetic reaction?

A

Solar energy + 6CO2 + 6H20 —> C6H12O6 + 602

40
Q

Chlorophyll

A
  • Green colour from chlorophyll pigments found within chloroplasts
  • chlorophyll traps sunlight
41
Q

What are chloroplasts? aka structure

A
  • double membrane
  • inside space is called stroma
  • in the stroma is the third membrane system
  • it’s called thylakoids sometimes stacked in grana
42
Q

Process of Cellular respiration (3 pts)

A
  • autotrophs (which carry out photosynthesis) and heterotrophs (which do not produce their own food) must convert glucose (sugar) into useful energy (ATP)
  • occurs in mitochondria
  • polysaccharides must be broken down first, and lipids must be converted to carbohydrates
43
Q

Cellular respiration reaction

A
  • energy from ADP to ATP given

C6H12O6 + 6O2 —> 6CO2 + 6H2O + (energy)

44
Q

Mitochondria:

What cells, what does it do, parts of it

A
  • in all eukaryotic cells
  • releases energy from sugars
    Two membranes:
  • Space inside inner membrane (matrix)
  • folds of inner membrane (cristae)
45
Q

Function of cristae

A
  • useful because More SA for ATP production

- The more surface area, the more membrane proteins necessary to carry out cellular respiration

46
Q

Summary reaction photosynthesis and cellular respiration

A
  • The summary reactions of both our exact opposite of each other
  • but each is made up of a large number of controlled reactions that occur step-by-step
  • This is called metabolic pathway
47
Q

What is metabolism?

A
  • all the chemical reactions that occur within a cell to support and sustain its life function
48
Q

What are the two categories of metabolism?

A

Anabolic metabolic pathways, and catabolic metabolic pathways

49
Q

What are anabolic metabolic pathways?

A
  • make larger molecules from smaller ones, and require energy
50
Q

What are catabolic metabolic pathways?

A
  • Break down larger molecules to smaller ones, and release energy
51
Q

Why are enzymes important in metabolism?

A
  • they lowered the amount of energy required to activate these reactions in cells, and speed them up
  • Enzymes are necessary every step of the way
52
Q

Lysosome and endocytosis reaction

A
  • lysosome produced from Golgi attaches to vesicle produced from endocytosis
  • the digestive enzymes in the lysosome break down the substances in the vesicle
  • digested materials diffuse into the cytoplasm
  • a residual body containing undigested material (waste) is formed
  • undigested material is excreted from the cell through exocytosis
53
Q

Why does osmosis happen?

A
  • the cell is surrounded by a semi- permeable membrane

- solutes may not be able to pass the membrane, but solvent (water) can