Biology Combined Science - Key Concepts and Terms

Vocabulary flashcards generated from the Combined Science Biology lecture notes covering characteristics of life, cellular structure, transport, biological molecules, enzymes, and plant nutrition.

Movement

An action taken by an organism or part of an organism that causes a change in place or position.

Respiration

A chemical reaction that takes place in cells to break down nutrient molecules and release energy.

Sensitivity

The ability to detect and respond to stimuli.

Growth

A permanent increase in size and dry mass, whether by an increase in cell number, cell size, or both.

Reproduction

The process of making more offspring of the same kind of organism.

Excretion

The removal of metabolic waste products and substances in excess of requirements from an organism.

Nutrition

Taking in materials and using them for energy, growth, and development.

Cell

The smallest building unit of a living organism.

Tissue

A group of similar cells working together to perform a specific function.

Organ

A group of different tissues working together to perform a specific function.

Organ System

A group of organs working together to perform a specific function.

Level of Organization

The hierarchical organization in living things: $\text{cell} \rightarrow \text{tissue} \rightarrow \text{organ} \rightarrow \text{organ system}$.

Animal Cell Structure

Cell structure composed of cell membrane, nucleus, cytoplasm, mitochondria, and ribosomes.

Plant Cell Structure

Cell structure composed of cell wall, cell membrane, nucleus, cytoplasm, mitochondria, ribosomes, large sap vacuole, and chloroplasts.

Cell Wall

A freely permeable cell structure made from cellulose that supports the cell to prevent it from bursting.

Cell Membrane

A partially permeable membrane that controls what enters and leaves the cell.

Cytoplasm

A jelly-like substance made mostly of water that serves as the site of cellular chemical reactions.

Chloroplasts

Organelles containing chlorophyll (green pigment) that trap light energy during photosynthesis and convert it to chemical energy.

Nucleus

Cellular organelle that controls cell activities because it contains DNA.

Sap Vacuole

A large organelle found in plant cells used for storage.

Mitochondria

The energy house of the cell where respiration occurs to release energy.

Ribosomes

Cellular organelles responsible for protein synthesis.

Bacterial Cell Structure

Structure of a bacterial cell showing capsule, cell wall, cell membrane, cytoplasm, circular DNA (nucleus), plasmid, ribosomes, and flagellum.

Root Hair Cell

Specialized cell found near root ends of plants with long thin extensions to increase the rate of absorption of water and mineral ions.

Palisade Mesophyll Cell

Specialized cell located beneath the leaf epidermis containing many chloroplasts for photosynthesis.

Red Blood Cell

Specialized cell in mammalian blood that functions to transport oxygen.

Magnification Formula

The formula defined as $\text{Magnification} = \frac{\text{Image Size}}{\text{Actual Size}}$.

Carbohydrates

Biological molecules made of carbon, hydrogen, and oxygen, formed from glucose chains into molecules such as cellulose, starch, and glycogen.

Fats

Biological molecules made of fatty acids and glycerol containing carbon, hydrogen, and oxygen (with less oxygen than carbohydrates).

Proteins

Biological molecules made of amino acids containing carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur and phosphorus.

Starch Test

Food test using iodine solution; a positive result yields a blue-black color, while a negative result remains brown.

Reducing Sugars Test

Food test using Benedict's solution and heat; a positive result produces a color spectrum ending in brick-red, while a negative result remains blue.

Biuret Test

Food test for proteins using Biuret reagent; a positive result turns purple, while a negative result remains blue.

Ethanol Emulsion Test

Food test for fats involving ethanol and water; a positive result turns milky, turbid, or cloudy, while a negative result remains clear.

Passive Transport

Movement of particles down a concentration gradient from high to low concentration without using energy.

Diffusion

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

Osmosis

The net movement of water molecules from a high water potential to a low water potential down a water potential gradient through a partially permeable membrane.

Turgidity

The state of a plant cell when placed in a dilute solution as water moves into the cell.

Flaccid

The limp state of a plant cell when placed in a concentrated solution as water moves out of the cell.

Plasmolysis

The process where cytoplasm pulls away from the cell wall when a plant cell loses significant water in a concentrated solution.

Active Transport

The movement of particles from a low concentration area to a high concentration area against a concentration gradient using energy from respiration.

Enzymes

Proteins that act as biological catalysts in metabolic reactions, speeding up reactions while remaining unchanged afterwards.

Active Site

The specifically shaped region on an enzyme complementary to a substrate where the reaction takes place.

Optimum Temperature

The temperature at which an enzyme works best, which is approximately $37\text{ }^{\text{o}}\text{C}$ in the human body.

Denaturation

A permanent structural change in an enzyme's active site (caused by high temperature or extreme pH) preventing substrate binding.

Photosynthesis

The process by which plants manufacture carbohydrates from raw materials using light energy.

Photosynthesis Word Equation

The chemical reaction written as $\text{Carbon Dioxide} + \text{Water} \frac{\text{Light}}{\text{Chlorophyll}} \text{Glucose} + \text{Oxygen}$.

Photosynthesis Chemical Equation

The balanced chemical equation $6CO_2 + 6H_2O \frac{\text{Light}}{\text{Chlorophyll}} C_6H_{12}O_6 + 6O_2$.

Chlorophyll

Green pigment found in chloroplasts that absorbs light energy and converts it to chemical energy in glucose during photosynthesis.

Leaf Cross-Section Structure

Internal leaf structure showing upper epidermis, palisade mesophyll, spongy mesophyll with air spaces, lower epidermis, guard cells, stomata, and vascular bundle.

Xylem

Vascular plant tissue that transports water and mineral ions in one direction and provides structural support via lignin.

Phloem

Vascular plant tissue that transports sucrose and amino acids.

Magnesium Ions (Plant Requirement)

Essential mineral ions required by plants to make chlorophyll; deficiency leads to yellow leaves.

Nitrates (Plant Requirement)

Essential mineral ions required by plants to produce amino acids and proteins for growth; deficiency leads to stunted growth and yellow leaves.