Cellular processes Flashcards
Name the type of cell:…
- no membrane bound organelles
- Small
- Relatively unstructured
- Not organised internally
- A type of cell wall.
Prokaryotic (bacterial) cells.
Name the type of cell:
- Membrane bound
-Larger than prokaryotic cells (many are multi-cellular organisms)
- More complex than prokaryotes
Eukaryotic cells.
Organelles definition
Specialised structures inside the cell that carry out various functions.
- Contains phospholipid bilayer made of two layers with hydrophobic tails and hydrophilic heads.
- Proteins move freely in this fluid/flexing structure
- Certain substances are able to move in and out of cell.
Cell membrane structure (semi-permeable)
Cell membrane function. (compartments)
Membranes create compartments, control entry and exit and allow cell communication.
- No energy required
- substances move from high to low concentration
- substances move with the concentration gradient
passive transport
Diffusion
passive transport
is the net movement of particles from an area of high concentration to an area of low concentration., until concentration equilibrium is met.
Factors that affect rate of diffusion
- size of molecules ( small molecules move faster)
- temperature (warmer molecules move faster
- state of matter (gas molecules move faster than liquids
- concentration of chemicals (greater concentrations gradient the faster the rate of diffusion.)
Diffusion of cells in relation to cell size.
Diffusion is less efficient when cells are larger.
As ratio of surface area to cell volume decreases.
Facilitated diffusion
- Passive transport
- Transportation of molecules that are too big to move across cell membrane.
- Requires proteins embedded in cell membrane.
- Proteins contain channels molecules diffuse through
- Transport molecules are specific.
Osmosis.
Transportations of water molecules from high water concentration to low water concentration. Transport molecules towards highest solute concentration.
Hypertonic solution
more solute than water molecules.
Hypotonic solution:
More water molecules than solute molecules.
Isotonic solution.
equal amounts of solute and water molecules.
If you put a cell in a hypertonic solution….
water moves from high water concentration to low concentration outside the cell.
If you put a cell in a hypotonic solution….
water moves from high water concentration to low water concentration, inside the cell.
A hypotonic solution can cause the cell to….
burst/ cell rupture.
A hypertonic solution can cause the cell to….
shrink.
Active transport
substances that require energy (ATP) to enter the cell. Substances travel against the concentration gradient.
How does ATP work in relation to creating energy and moving molecules against concentration gradient.
- ATP binds to transport protein.
- Molecule/ ion binds to protein.
- Water is added to ATP, and energy (phosphate) is released and ADP is formed - molecule moves across membrane)
- molecule is released.
What is endocytosis? Active or passive transport?
infolding of membrane to form vesicles that enter cytoplasm. If it contains liquid it is Pinocytosis. And if it’s solid it is Phagocytosis.
Active transport
What is exocytosis. Is it passive or active transport?
vesicles from intracellular environment fuse with membrane and releases content outside of cell.
Active transport.
Carrier proteins: Ion pumps
Active or passive?
are transmembrane proteins that use energy to move ions.
Active transport.
- made of proteins
- speed up chemical reactions in cytoplasm.
- needed only in small amounts
- remain unchanged after reaction.
- specific for a substrate.
Properties of Enzymes.
Plasmolysis
Membrane that pulls aways from the cell wall. This happens when cell shrinks inside its cell wall while the cell wall remains intact.
Anabolic reactions
small molecules assembled into larger ones. Energy is required.
Catabolic reactions
larger molecules are broken down into smaller ones.
Energy is released.
Lock and key model.
Substrate has specific shape which fits perfectly into enzyme’s active site
Induced fit model
enzymes active site is flexible and changes to fit substrate.
How enzymes work - induced fit model
enzymes active site is flexible and changes to fit substrate. One reaction is finished, substrate is released and active site changes back to original shape.
Particles theory
Matter is made up of particles that are in constant motion. Temperature affects the speed of these particles.
Collision theory
reactants must collide at correct orientation with sufficient force to overcome activation energy.
Activation energy
minimum amount of energy required for a chemical reaction to take place.
Enzymes lower activation energy by….
providing an alternative pathway of lower activation energy.
Factors affecting reaction rate (4) (hint: enzymes)
pH
Temperature
Substrate concentration
Enzyme inhibitors.
How does pH affect enzymes.
Enzymes have optimum pH. Outside of pH range, enzymes denature.
Enzyme cofactor
non-protein chemical binds to enzyme to make active site functional.
Enzyme competitive inhibitors.
bind to active site and stop substrate from binding.
Enzyme non-competitive inhibitors.
bind outside active site changing enzyme’s shape so it can’t bind.
What happens to enzyme structure when it denatures.
hydrogen and disulphide bonds within the protein molecule , which give it its shape, are broken.
Rate of reaction before enzymes have reached optimum temperature.
Enzyme and substrate don’t have enough kinetic energy to collude effectively at correct orientation to lower activation energy, and speed up rate of reaction. Tho rate of reaction increases with increasing temperature……
Rate of reaction at enzyme’s optimum temperature
- highest rate of enzyme reaction
- successful binding
- lower activation energy
Rate of reaction above enzyme’s optimum temperature.
hydrogen and disulfide bonds break
Enzymes denature.
Reaction rate decreases.
respiration definition.
process that occurs in the mitochondria. Glucose is broken down into ATP.
ATP definition
energy molecules used to fuel chemical reaction within the cell.
Where does respiration occur
- in the cytoplasm (Glycolysis)
- in Mitochondria
Aerobic respiration
- Respiration is the presence of oxygen
- Oxygen is required to break down glucose into carbon dioxide and water.
- Energy is released in the form of ATP and heat.
Aerobic respiration chemical reaction formula
C(6)H(12)O(6) + 6O2 → 6CO(2) + 6H(2)O + 36 ATP
Anaerobic respiration
- respiration in absence of oxygen
- Occurs in animals when there is a shortage of oxygen
- Only 2 ATP molecules are produced.
- If this occurs in muscle cells lactic acid is produced, or in yeast, ethanol and CO2 is produced.
What is the word equation for anaerobic respiration?
Glucose → 2ATP + Lactic acid.
Cell cycle
Sequence of events that occur in a cell in preparation of cell division.
Interphase of cell cycle definition.
time when cell is not dividing and is instead growing and carrying out other cell processes.
What is G1 of interphase?
Growth phase where organelles are duplicated (not chromosomes.)
What is S phase in interphase in cell cycles?
When DNA is replicated.
What is G2 in interphase in cell cycle?
Copied DNA is ‘spell checked.’ More growth if needed. enzymes are made. Getting ready for dividing
What is mitosis in cell cycles?
cell division and reproduction of somatic cells.
What is cytokinesis in cell cycle?
when cell splits into two cells.
What factors increase respiration rate?
- Increasing oxygen concentration.
- High concentration of glucose
- Enzymes at optimum temperature
- absence of inhibitors.
What limits respiration….
- low concentration of reactants.
- Increase in lactic acid - lowers pH (enzymes denature)
How does temperature affect enzyme
Outside of a range around optimum temperature, enzymes denature.
How does increase in oxygen increase respiration rate?
- aerobic respiration rate will take place allowing lots of ATP to be produced.
How does cell’s demand for energy affect respiration?
higher demand for ATP causes respiration rate to increase.
How does glucose concentration affect respiration?
more glucose means higher rate of respiration.
Anaerobic metabolism: fementation
- fermentation is an anaerobic process that passes electrons directly to the final electron acceptor:
Photosynthesis
process where light is used to react carbon dioxide and water to form glucose and oxygen. Photosynthesis uses chlorophyll pigment inside chloroplast to capture this light energy.
Photosynthesis formula equation.
6CO2 + 6H2O → C6H12O6 + 6O2
Where does the light dependent phase of photosynthesis occur?
lumen of the thylakoid.
What happens during the light dependent phase of photosynthesis.
- Light captured splits water molecules into H+ ions and O2.
- Protons are transferred to the NADPH molecule.
- The protons move back through the membrane from the lumen to stroma and ADP is converted to ATP by ATP synthase enzyme.
Where does the light independent phase occur in photosynthesis.
In the stroma of chloroplasts.
What happens during light independent phase in photosynthesis.
ATP and NADPH combine with RuBP and Carbon dioxide and are converted into G3P by RuBisCO enzyme.
G3P is converted into glucose.
Leaf adaptions (shade leafs)
Shade leafs are larger and thinner (sun only gets through a few layers and less energy to make cells)
Leaf adaptions (sun leafs)
Smaller and thicker as there are longer and more palisade layers and sun penetrates farther.
What light does chlorophyll absorb, and what light is reflected.
Absorbs red and blue light and reflects green light. This is why leaves appear green.
*carotenoids are pigments that absorb various wavelengths of light.
Leaf shape adaptions (shaded leaves)
- have better ability to use far-red light.
- Grow broader and thinner to catch more sunlight.
- Greater mass of chlorophyll.
