Cell Processes

Osmosis

The net movement of water molecules across a semi permeable membrane from a area of high concentration, to a area of low concentration down a concentration gradient.

Osmosis

The net movement of water molecules across a semi permeable membrane down a concentration gradient from a area of high concentration to a area of low concentration.

Active transport

The movement of molecules against the concentration gradient from low to high concentration requiring ATP

Facilitated diffusion

The movement of molecules down a concentration gradient through a carrier protein requiring no ATP

Passive transport

The movement of molecules across the cell membrane without requiring cellular energy

Selectively permeable

Only allows certain substances to travel through the membrane

Equilibrium

A state of balance where there is not net movement of particles in or out of the cell as the concentration levels are equal on both sides of the semi permeable membrane

Concentration gradient

The difference in concentration of molecules between connected areas within a cell

Hypertonic solution

A solution with a higher solute concentration than the cell, acsuing water to move out the cell via osmosis

Hypotonic solution

A solution with a lower solute concentration than the cell causing water to move into the cell via osmosis

Isotonic solution

A solution with the same solute concentration as the cell meaning there is no net movement of water

SA:V ratio

The amount of surface area compared to the volume of the cell, affecting how efficiently substances move in and out

Importance of SA:V ratio

Larger SA:V ratio area allows substances to move in and out the cell more efficiently

Exchange of materials

The movement of substances such as carbon dioxide, oxygen, nutrients and waste products between the cell and its surroundings

Enzyme

A biological catalyst made of protein that speeds up the rate of reaction in cells without being used up

Substrate

Binds with a enzyme to make a enzyme substrate complex and is the substance a enzyme acts on during a chemical reaction

Active site

The region on the surface of the enzyme where substrate binds to the complimentary shape

Enzyme specificty

Each enzyme only works with certain substrates because of the active sites specific shape

Enzyme substrate complex

A temporary structure formed when a substrate bond to a enzymes active site

Activation energy

The minimum amount of energy required for a chemical reaction to occur

Optimum temperature

The temperature when a enzyme is working at its fastest rate

Denaturing

When the active site of a enzyme is changed so the substrate can no longer bind

Effect of high temperatures on enzymes

High temperatures cause enzymes to denature breaking the enzyme substrate complex bond

Low temperature effect on enzymes

Low temperatures result in less activation energy therefore less collisions are occurring so less enzyme substrate complexes are formed because of the reaction rate slowing

Effect of pH on enzymes

Can change the enzymes active site shape so the substrate may no longer fit

Enzyme inhibitor

A molecule that binds to a enzyme that decreases or stops a enzyme from forming a enzyme substrate complex

Substrate concentration

Increasing the substrate concentration means there is increased enzyme activity until all active sites become occupied

Photosynthesis equation

carbon dioxide + water = glucose + oxygen

Light dependent reaction

Reactions that occur in the thylakoid membranes where chlorophyll absorbs light energy, splitting water molecules to produce ATP and a waste product of oxygen

Light independant reaction

Reactions that occur in the stroma where carbon dioxide produces sugars

Chlorophyll

A green pigment that absorbs light energy used in photosynthesis

Factors that effect rate of photosynthesis

Light intensity, carbon dioxide concentration, temperature

Effect of high light intensity

Increases rate of reaction because more light energy is available

Effect of carbon dioxide concentration

Increases rate of photosynthesis because more raw material is available

Effect of temperature on photosynthesis

increases the rate of enzyme controlled reactions up to optimum temperature and after the high temperatures may start to denature enzymes so enzyme substrate coalitions decrease

Photolysis

The splitting of water molecules using light energy, producing oxygen, hydrogen ions and electrons.

Cellular resperation

The process where glucose is broken down to produce energy, this is transferred into ATP for cellular activity’s

Aerobic resperation

Glucose + oxygen - carbon dioxide + water + 36 ATP

Electron transport chain

A series of proteins complexes in the mitochondria that transfer electrons and help to produce large amounts of ATP

Anaerobic respiration

The release of energy from glucose without oxygen producing less ATP than Aerobic resperation

ATP

A energy molecule that stores and transfers energy to cell processes such as active transport

Glycolysis

The first stage of cellular respiration where glucose is broken down in the cytoplasm producing a small amount of ATP

Krebs cycle

A series of reactions in the mitochondria that break down products of glucose and release carbon dioxide and energy carrying molecules

Role of oxygen in respiration

Oxygen acts as the final electron acceptor in the electron transport chain, allowing aerobic respiration to continue and large amounts of ATP to be produced.

Effect of low oxygen concentration

Limits aerobic respiration because less oxygen is available for the electron transport chain this reduces ATP production

DNA replication

The process where DNA makes a identical copy of itself before cell division so the daughter cell receives identical genetic information

mitosis

The division of a cell into two identical daughter cells into two genetically identical sets of chromosomes

Mitosis purpose

Mitosis allows organisms to grow, repair damaged tissues and replace old or damaged cells while maintaining the same genetic information.

Interphase

The stage of the cell cycle where the cell grows and replicates DNA for cell division