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yr.11 Biology > cell structures and processes > Flashcards

cell structures and processes Flashcards

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1
Q

Cell membrane

A

forms boundary between internal environment and cytoplasm.
Functions are: recognition of other cells, transportation of material in and out of cell, provision of attachment sites for enzymes and hormones

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2
Q

fluid mosaic model

A

Double layer of lipids, lipid bilayer
ability to flow and change shape
Proteins embedded in layer

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3
Q

phospholipid

A

Phosphate group of head is hydrophilic

fatty acid tail is hydrophobic

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4
Q

Cholesterol in phospholipid bilayer

A

lipid in membrane

Helps maintain cell membrane stability at varying temps

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5
Q

transmembrane proteins

A

Proteins that extend across the entire membrane, past heads and tails
Function as transport proteins by, controlling entry and exit of substances, and act as passageways for specific substances
2 types: channel proteins, carrier proteins

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6
Q

channel protein

A

Passive transport/facilitated diffusion, don’t require energy
open and close in response to a stimuli

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7
Q

aquaporins

A

Channel protein

facilitates transport of water along concentration gradient

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8
Q

Carrier proteins

A

Binds to a specific molecule, changes shape and releases the substance on the other side
Uses energy

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9
Q

adhesion protein

A

Link cells together to maintain both 3D structure and normal functioning of tissues

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10
Q

receptor protein

A

Bind hormones and other substances that cause changes to the cell’s activities

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11
Q

Passive transport

A

movement of substances that don’t require energy

Move down concentration gradient

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12
Q

simple diffusion

A

Net movement of particles from region of high concentration to lower particle concentration
difference between concentrations is the concentration gradient
Occurs because of random kinetic movement of particles
Is a passive process

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13
Q

equilibrium

A

Particles are evenly spread out, therefore no concentration gradient

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14
Q

Diffusion across membrane

A

small uncharged molecules can pass through phospholipid bilayer

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15
Q

Facilitated diffusion

A

charged or large molecules don’t pass through phospholipid bilayer
2 proteins assist: carrier proteins and channel proteins
No energy required

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16
Q

osmosis

A

Diffusion of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration.
water moves passively past phospholipids

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17
Q

Isotonic

A

Same concentration of solute in cell and outside of cell.

no net change across membrane

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18
Q

Hypotonic

A

external solution contains less solute

Water diffuses into cell to balance H2O concentration

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19
Q

hypertonic

A

External has higher solute concentration

water diffuses from cell to outside

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20
Q

Osmosis in plants

A

plant contains large vacuole with solute

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21
Q

Turgid

A

hypotonic solution surrounds plant cell
Water diffuses firstly into cytosol, then into vacuole, vacuole swells, pushing cytoplasm and cell membrane against cell wall.
cell wall prevents bursting
When membrane stretched to max possibility, no more water can enter

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22
Q

plasmolysis

A

Water diffuses out, reducing volume of vacuole and causing cells to become limp or placid, plant will wilt.
if enough water lost, cell membrane pulls away from cell wall

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23
Q

Active transport (carrier proteins)

A

requires energy
Performed by proteins
can go against concentration gradient
Act as one way valve

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24
Q

Endocytosis

A

movement of solids or liquids into a cell from the environment via vesicle formation
Membrane changes shape by sending out projections that surround the prey, when projections meet, membrane fusion occurs

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25
Q

phagocytosis

A

Endocytosis of solids

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26
Q

pinocytosis

A

Endocytosis of liquids

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27
Q

recognition protein

A

Protein that acts as a marker on membranes

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28
Q

exocytosis

A

Process by which large molecules held in vesicles within the cell are transported to external environment
membrane-bound vesicle fuses to membrane and then releases its contents to exterior of the cell

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29
Q

Metabolism

A

sum of all biochemical processes occurring in an organism

30
Q

Anabolic reactions

A

involve synthesis of complete molecules from simpler ones and usually require energy to form new chemical bonds

31
Q

Catabolic reactions

A

involve breakdown of complex molecules into simpler ones and usually releases energy from breaking chemical bonds

32
Q

Biochemical processes

A

chemical reactions in a cell occur in a series of regulated steps
Provides enough energy to maintain the processes of generating products from reactants

33
Q

enzyme

A

Biological catalyst that speeds up biological reactions without undergoing any change itself
macromolecules
Lower activation energy required for a reaction to proceed

34
Q

cellular metabolism

A

Sum of thousands of chemical reactions that occur constantly in each living cell
rate varies in organisms

35
Q

Exergonic reactions

A

releases energy

When moleculer bonds are broken, energy is released

36
Q

endergonic reactions

A

Energy is used

cells use energy released from catabolic reactions used for anabolic reactions

37
Q

Activation energy

A

minimum amount of initial energy required to start a chemical reaction
Usually applied in heat energy

38
Q

active site

A

Place on surface of an enzyme molecule where substrate molecules attach

39
Q

substrate

A

A reactant on which an enzyme acts

40
Q

enzyme-substrate-complex

A

Substrate must be of a compatible shape for binding to occur

41
Q

Lock-and-key model

A

substrate must be of a compatible shape for binding to occur
Substrate fits active site of enzyme like lock-and-key

42
Q

induced-fit model

A

Enzyme not shaped
bonds between enzyme and substrate slightly modify enzyme so that substrate can be accommodated by enzyme
Bonds within substrate molecule are stretched and bent by molecular interactions with amino acid groups that live active site, activation energy required drastically lowered
After product released, active site returns to OG shape

43
Q

psychrophile

A

An orgasm that lives in extremely cold conditions

enzymes can operate at low temps

44
Q

Thermophile

A

an organism that .ives in high temperature environments

Operates best at 95-105C

45
Q

temperature and enzymes

A

As temps increases, molecules become more active and collide more often
temp too high and could denature enzyme
Lower temp means lower rate of enzyme activity, lower rate of reaction

46
Q

pH on enzymes

A

Enzymes have optimal pH for reactions

active site shape can change due to pH, therefore denatures

47
Q

Inhibitors

A

a substance that competes with substrate for an enzyme’s active site

48
Q

Cofactor

A

small, inorganic substance that must be present in addition to an enzyme to catalyse a certain reaction

49
Q

Coenzymes

A

non-protein organic substance that are required for enzyme activity
Relatively small compare to enzymes

50
Q

ATP

A

Main energy carrying molecule used in metabolism
energy enters ecosystem through light energy
energy can be transferred between reactions
Nucleotide containing adenosine attached to a sugar group (ribose) and chain of 3 phosphate groups
when 3rd phosphate of chain breaks off it releases energy

51
Q

Photosynthesis

A

biochemical process, in producers, that uses light energy and the raw materials carbon dioxide and water to synthesise organic compounds

52
Q

ADP

A

When ATP has 2 phosphates left
energy has been released
Adenine Diphosphate

53
Q

phosphorylation

A

When bond forms between an available phosphate group and ADP, producing ATP

54
Q

Chloroplast

A

light captured by chlorophyll pigment found in chloroplast organelle
Has outer and inner membrane

55
Q

stroma

A

Enclosed inner membrane

gel-like matrix rich in enzymes

56
Q

Thylakoid membranes

A

suspended in stroma

Flat, sac-like structures called grana, granum singular

57
Q

light dependent stage

A

when chlorophyll molecule in thylakoid membranes absorbs light energy, electron within become energised.
Energy used to split H2O in hydrogen ions (H) and oxygen gas (O2)
ATP molecules formed at this stage
Electron donated to NADP to form NADPH
light absorbed by three pigments: chlorophyll (green), Carctenoids (orange), and Xanthophylls (yellow)

58
Q

Chlorophyll

A

absorbs red and blue light

Reflects green

59
Q

light independent stage

A

occurs in stroma (fluid part) of the chloroplast
Glucose molecules created from CO2 and Hydrogen ions
Requires supply of CO2 and Hydrogen ions in NADPH and ATP
ATP made by dependent light stage provide chemical energy for conversion of carbon dioxide to glucose molecules
Reactions are anabolic, result in carbon being stored in glucose (carbon fixation)

60
Q

During day (photosynthesis)

A

Chloroplasts convert newly formed glucose molecules to sucrose of starch

61
Q

at night (light independent stage)

A

Cell converts starch to sucrose for export to other cells in leaves, stems and roots that lack chloroplasts

62
Q

Cellular respiration

A

biochemical process
Occurs in cytosol and mitochondria
metabolises organic compounds, aerobically or anaerobically to release usable energy in form of ATP

63
Q

Aerobic respiration

A

series of reactions in presence of O2, by which organisms obtain energy from organic molecules, via production of ATP
glycolysis, citric acid cycle (Krebs cycle) and electron chain transport
Glucose combines with oxygen to produce ATP
occurs in mitochondria
Process can proceed without O2, site for this reaction is cytoplasm

64
Q

glycolysis

A

Takes place in cytosol
biochemical pathway made up of 10 reactions, each step controlled by enzyme
Initial reaction is glucose and final product from each molecule of glucose is 2 molecules of a compound called pyruvate

65
Q

mitochondria

A

Produces large amounts of ATP
site of aerobic respiration
Inner and outer membrane and inner membrane space

66
Q

cristae

A

Structure formed by heavily folded inner membrane of mitochondria
Embedded are enzymes called Adenosine Triphosphate (ATP) synthase
contains respiratory electron transfer chain proteins and transport proteins

67
Q

Matrix

A

site for citric acid cycle

Space within inner membrane

68
Q

Anaerobic respiration

A

takes place in cytosol in the absence of O2

Alcohol fermentation and lactic acid fermentation

69
Q

alcohol fermentation

A

CO2 and ethanol
Products: glucose -> ethanol + CO2 + 2 ATP
ethanol is toxic therefore cell must revert to aerobic respiration other wise will be poisoned by ethanol

70
Q

Lactic acid fermentation

A

end product of anaerobic respiration in animals
Lactic acid converted back to pyruvate allowing continued aerobic respiration
Glucose -> lactic acid + 2 ATP

71
Q

Compensation point

A

when uptake of CO2 from photosynthesis is equal to output of CO2 from aerobic respiration

yr.11 Biology (8 decks)

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