Level 2 Biology: Life Processes at the Cellular Level

Vocabulary flashcards covering cellular organelles, enzyme kinetics, transport mechanisms, photosynthesis, respiration, and cell division.

Phospholipid bilayer

The structure of the cell membrane, consisting of two rows of phospholipids, each with a phosphate head and fatty acid tails.

Cell Membrane

A structure that surrounds the cell, controls what enters and exits to stop harmful substances, and helps maintain cell structure.

Cytoplasm

The jelly-like material inside all cells that contains nutrients and allows organelles to float within it.

Nucleus

The control centre of the cell which has a double membrane and contains DNA with the instructions for the cell.

Mitochondria

Organelles known as the 'powerhouses of the cell' that make energy from sugar through respiration to power cell processes.

Cristae

The wavy folds of the inner mitochondrial membrane that increase surface area for more efficient reactions and energy production.

Chloroplasts

Organelles in plants with a smooth double membrane that carry out photosynthesis by trapping light energy to make sugar.

Thylakoid

An individual disk found inside a chloroplast; stacks of these disks are known as grana.

Stroma

The clear liquid surrounding the grana stacks inside a chloroplast that allows maximum light to reach the chlorophyll.

Cell Wall

A rigid outer layer found only in plant cells that provides shape and structure.

Enzymes

Biological catalysts made of protein that speed up reactions without being used up.

Active site

The specific region of an enzyme where substrates bind for the enzyme to speed up the reaction.

Lock and key model

A model where the substrate (the key) fits into the enzyme’s active site (the lock) because their shapes match perfectly.

Induced fit model

The actual way enzymes work, where the active site and substrate slightly change shape to fit together.

Enzyme saturation

The point where increasing substrate concentration no longer increases the rate of reaction because all available enzymes are busy.

Denaturing

A process where high temperatures cause the active site of an enzyme to lose its normal shape, stopping its activity.

Competitive Inhibitors

Substances that bind directly to the enzyme’s active site to reduce or stop activity.

Non-competitive Inhibitors

Substances that bind to a part of the enzyme other than the active site, changing its shape to reduce activity.

Diffusion

The movement of substances from high to low concentration without the use of energy.

Osmosis

The passive movement of water from a high concentration to a low concentration.

Facilitated diffusion

The movement of larger molecules across the cell membrane using special channels and proteins without needing energy.

Active Transport

The movement of substances against a concentration gradient (low to high) using ATP energy and special pumps.

Endocytosis

The active process of moving material into a cell by forming sacs using sections of the cell membrane.

Exocytosis

The active process of moving material out of a cell by forming sacs and combining them with the cell membrane.

Photosynthesis Word Equation

$$\text{Water} + \text{Carbon dioxide} + \text{Light energy} \rightarrow \text{Glucose} + \text{Oxygen}$$

Photosynthesis Balanced Symbol Equation

$$6H_2O + 6CO_2 + \text{Light energy} \rightarrow C_6H_{12}O_6 + 6O_2$$

Light-dependent reactions

The stage of photosynthesis that uses light to split water into hydrogen and oxygen.

Light-independent reactions

The stage of photosynthesis, also called the Calvin cycle, that produces glucose.

Aerobic respiration

A process using glucose and oxygen to create ATP energy, with water and carbon dioxide as waste products.

Aerobic Respiration Balanced Symbol Equation

$$C_6H_{12}O_6 + 6O_2 \rightarrow \text{ATP} + 6H_2O + 6CO_2$$

Anaerobic Respiration (Fermentation)

A process occurring in limited oxygen that produces a small amount of ATP and lactic acid (in muscles).

Cell Cycle Stages

The four phases: G1 (cell growth), S (DNA replication), G2 (continued growth), and M (mitosis).

Semi-conservative Replication

The replication of DNA where each new molecule has one strand from the old chromosome and one new strand.

Mitosis

Cell division producing two identical daughter cells for body growth and repair.

Stages of Mitosis

The sequence consisting of Interphase, Prophase, Metaphase, Anaphase, and Telophase.