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yr.11 Biology > cell structures and processes > Flashcards

cell structures and processes Flashcards

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
phagocytosis
Endocytosis of solids
26
pinocytosis
Endocytosis of liquids
27
recognition protein
Protein that acts as a marker on membranes
28
exocytosis
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
29
Metabolism
sum of all biochemical processes occurring in an organism
30
Anabolic reactions
involve synthesis of complete molecules from simpler ones and usually require energy to form new chemical bonds
31
Catabolic reactions
involve breakdown of complex molecules into simpler ones and usually releases energy from breaking chemical bonds
32
Biochemical processes
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
enzyme
Biological catalyst that speeds up biological reactions without undergoing any change itself macromolecules Lower activation energy required for a reaction to proceed
34
cellular metabolism
Sum of thousands of chemical reactions that occur constantly in each living cell rate varies in organisms
35
Exergonic reactions
releases energy | When moleculer bonds are broken, energy is released
36
endergonic reactions
Energy is used | cells use energy released from catabolic reactions used for anabolic reactions
37
Activation energy
minimum amount of initial energy required to start a chemical reaction Usually applied in heat energy
38
active site
Place on surface of an enzyme molecule where substrate molecules attach
39
substrate
A reactant on which an enzyme acts
40
enzyme-substrate-complex
Substrate must be of a compatible shape for binding to occur
41
Lock-and-key model
substrate must be of a compatible shape for binding to occur Substrate fits active site of enzyme like lock-and-key
42
induced-fit model
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
psychrophile
An orgasm that lives in extremely cold conditions | enzymes can operate at low temps
44
Thermophile
an organism that .ives in high temperature environments | Operates best at 95-105C
45
temperature and enzymes
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
pH on enzymes
Enzymes have optimal pH for reactions | active site shape can change due to pH, therefore denatures
47
Inhibitors
a substance that competes with substrate for an enzyme’s active site
48
Cofactor
small, inorganic substance that must be present in addition to an enzyme to catalyse a certain reaction
49
Coenzymes
non-protein organic substance that are required for enzyme activity Relatively small compare to enzymes
50
ATP
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
Photosynthesis
biochemical process, in producers, that uses light energy and the raw materials carbon dioxide and water to synthesise organic compounds
52
ADP
When ATP has 2 phosphates left energy has been released Adenine Diphosphate
53
phosphorylation
When bond forms between an available phosphate group and ADP, producing ATP
54
Chloroplast
light captured by chlorophyll pigment found in chloroplast organelle Has outer and inner membrane
55
stroma
Enclosed inner membrane | gel-like matrix rich in enzymes
56
Thylakoid membranes
suspended in stroma | Flat, sac-like structures called grana, granum singular
57
light dependent stage
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
Chlorophyll
absorbs red and blue light | Reflects green
59
light independent stage
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
During day (photosynthesis)
Chloroplasts convert newly formed glucose molecules to sucrose of starch
61
at night (light independent stage)
Cell converts starch to sucrose for export to other cells in leaves, stems and roots that lack chloroplasts
62
Cellular respiration
biochemical process Occurs in cytosol and mitochondria metabolises organic compounds, aerobically or anaerobically to release usable energy in form of ATP
63
Aerobic respiration
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
glycolysis
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
mitochondria
Produces large amounts of ATP site of aerobic respiration Inner and outer membrane and inner membrane space
66
cristae
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
Matrix
site for citric acid cycle | Space within inner membrane
68
Anaerobic respiration
takes place in cytosol in the absence of O2 | Alcohol fermentation and lactic acid fermentation
69
alcohol fermentation
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
Lactic acid fermentation
end product of anaerobic respiration in animals Lactic acid converted back to pyruvate allowing continued aerobic respiration Glucose -> lactic acid + 2 ATP
71
Compensation point
when uptake of CO2 from photosynthesis is equal to output of CO2 from aerobic respiration

yr.11 Biology (8 decks)

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