Cellular Processes

Flashcards for cell biology exam review.

Unicellular Organism

An organism that consists of one independent cell.

Multicellular Organism

An organism that consists of more than one cell. Each cell has different functions and structures.

Prokaryote

A cell type without a nucleus.

Eukaryote

A cell type with a nucleus.

Specialized cells

Cells in multicellular organisms adapted for specific functions.

Plant cells

Eukaryotic cells present in green plants. Plant cells have certain features like chloroplasts, cell walls, and intracellular vacuoles.

Cell Wall

Tough external outer covering. It provides support and strength; prevents excess water uptake

Chloroplast

The site of photosynthesis in plant cells; gives the cell its characteristic green color.

Large Central Vacuole

Assists with storage and structure in plant cells.

Animal Cells

Eukaryotic cells that make up the tissues and organs of animals.

Cell Membrane (Animal Cell)

Surrounds the animal cell and controls the passage of nutrients and chemicals; flexible and allows the cell to change shape.

Enzyme

A biological catalyst that speeds up the rate of reactions or allows reactions to take place.

Enzyme Action

Enzymes speed up chemical reactions because they reduce the stability of bonds in the reactants, providing an alternative energy pathway with lower activation energy.

Substrate

The molecule that fits into an enzyme

Active site

The place on the enzyme that the substrate fits

Enzyme Specificity

Enzymes are specific meaning they only work on one type of reaction due to the shape of their active sites.

Denaturation

Loss of an enzyme's three-dimensional structure, resulting in loss of catalytic activity.

Enzyme Optimum pH

The pH at which an enzyme will work best.

Substrate Concentration

Affects enzyme activity; the greater the substrate concentration, the higher the rate of reaction until all enzyme is 'busy'.

Enzyme Concentration

Affects the rate of reaction; as the amount of enzyme increases, activity will increase if there is sufficient substrate available.

Co-factor

Cannot be made in the body but interacts with enzymes so they can function.

Inhibitors

Competitive: Similar shape to substrate so it blocks the active site and alter its shape.

Fluid Mosaic Model

Describes the cell membrane as fluid because phospholipids and proteins can move freely and mosaic because of the scattered protein molecules.

Semipermeable Membrane

Allows small molecules and larger hydrophobic molecules to move through easily by diffusion.

Diffusion

The net movement of particles from an area of high concentration to low concentration.

Simple Diffusion

Molecules can freely move through a membrane.

Facilitated Diffusion

for big and charged particles they can pass through protein channels

Osmosis

The diffusion of water molecules through a semipermeable membrane from where water is in higher concentration to where it is in lower concentration.

Active Transport

Moving ions and molecules from an area of low concentration to high concentration using energy.

Photosynthesis

Carbon Dioxide + Water → Glucose + Oxygen.

Photosynthesis stages

1. The light phase in the grana (stacks of thylakoids) 2. The dark phase /calvin cycle in the stroma (the liquid inside the chloroplast)

Chlorophyll

Absorbed light waves are red and blue/violet.

Light Dependent Reaction

It occurs in the thylakoid membranes. Water enters and the energy from light splits water into hydrogen and oxygen. Oxygen is released and ATP (energy) is also produced.

Light Independent

It occurs in the stroma of chloroplast. Carbon dioxide (CO2) and hydrogen from light dependent enter the chloroplast and they combine carbon + hydrogen and leave the reaction as glucose, there will be excess Hydrogen and carbon released. ADP is converted to form ATP.

Respiration

Respiration occurs in the mitochondria

Glucose + Oxygen → Carbon Dioxide + Water + ATP + Heat

Aerobic Respiration

This takes place in the mitochondria.

Glucose + Oxygen → Carbon Dioxide + Water + Energy (ATP)

Glycolysis - Enzyme Controlled reaction that involves Aerobic Respiration.

Occurs in the cytoplasm, it happens in the first stages of both aerobic and anaerobic respiration. One molecule of glucose and 2ATP is used to produce two pyruvate molecules, hydrogen ions, and 4ATP

Krebs Cycle - Enzyme Controlled reaction that involves Aerobic Respiration.

Occurs in the matrix of the mitochondria, it happens in the 2 stage of aerobic respiration. It uses pyruvate from glycolysis and produces Carbon dioxide, ATP, and water

Electrons transfer chain - Enzyme Controlled reaction that involves Aerobic Respiration.

Occurs in the inner mitochondrial membrane – cristae, it happens in the 3rd stage of aerobic respiration and it uses energy from the kerb cycle and oxygen so it can produce ATP and Water.

Anaerobic respiration

Breakdown of chemical energy (glucose) into pyruvate in the absence of oxygen to convert into lactate and produce small amount of energy in the form of ATP.

Glucose → Lactic Acid + Energy (ATP)