8.1 Organisms: Organisation, Skeleton, Movement, Cells, and Unicellular Organisms (Notes 1–17)

Vocabulary flashcards covering levels of organisation, the skeleton, joints, muscles, cells, plant and animal cell components, unicellular organisms, and basic innate processes like diffusion and photosynthesis.

Cell

The building block of life and the first level of organisation in living things.

Tissue

A group of similar cells that work together to perform a function.

Organ

A structure made of different tissues that work together to carry out a function.

Organ system

A group of different organs that work together to perform a function.

Hierarchy of organisation

Five levels in multicellular organisms: cell, tissue, organ, organ system, and organism.

Nerve tissue

Tissue of nerve cells that transmit messages around the body.

Muscle tissue

Tissue whose cells contract to cause movement.

Xylem

Plant tissue that transports water around the plant.

Animal cell

A cell from animals; typically has nucleus, cell membrane, cytoplasm, and mitochondria.

Plant cell

A cell from plants; contains nucleus, cell membrane, cytoplasm, mitochondria, plus a cell wall, vacuole, and chloroplasts.

Nucleus

Controls the cell and contains genetic material.

Cell membrane

Barrier around the cell that controls entry and exit of substances.

Cytoplasm

Jelly-like substance where chemical reactions occur.

Mitochondria

Organelles where respiration happens to release energy.

Cell wall

Rigid layer made of cellulose that strengthens and supports plant cells.

Vacuole

Permanent organelle containing cell sap; helps keep the cell firm.

Chloroplasts

Organelle where photosynthesis happens; contains chlorophyll.

Chlorophyll

Green pigment that traps light energy for photosynthesis.

Specialised cells

Cells that have changed to perform specific jobs in an organism.

Nerve cells

Long, thin cells that transmit electrical impulses between parts of the body.

Red blood cells

Cells that transport oxygen; contain haemoglobin and have no nucleus; disc-shaped for surface area.

Haemoglobin

Protein in red blood cells that binds to oxygen.

Sperm cells

Male gametes; have streamlined head and tail; contain many mitochondria to swim toward the egg.

Leaf cells

Plant cells in leaves; long and thin, packed with chloroplasts, and with a large surface area for photosynthesis.

Root hair cells

Root epidermal cells with long extensions; absorb water and nutrients; have no chloroplasts.

Diffusion

Movement of particles from a region of high concentration to low concentration.

Water diffusion (in plants)

Water moves from soil into root hairs (high to low water concentration) and through the plant by diffusion.

Amoeba

Unicellular organism with no fixed shape; moves by changing shape and engulfs food; reproduces by binary fission.

Engulfing

Process of surrounding particles to form a food vacuole for digestion.

Binary fission

Asexual reproduction in unicellular organisms where the cell divides into two.

Euglena

Unicellular organism with chloroplasts; can photosynthesize; has an eye spot and a flagellum.

Eye spot

Light-detecting structure in euglena to sense light.

Flagellum

Tail-like structure that propels the organism.

Photosynthesis

Process by which chloroplasts trap light energy to make sugar.

Bone

Living tissue in bones with a blood supply; minerals make it strong but flexible.

Bone marrow

Soft tissue inside some bones that produces red blood cells and some white blood cells.

Skeleton

All the bones in the body forming a framework for support and movement.

Joints

Where two or more bones meet; some joints are flexible, others rigid.

Cartilage

Smooth tissue covering the ends of bones in joints to reduce friction and protect bones.

Ligaments

Connect bone to bone and provide joint stability.

Tendons

Connect muscle to bone and transmit muscular force.

Hinge joints

Joints that move backwards and forwards (e.g., knee and elbow).

Ball and socket joints

Joints that allow movement in all directions (e.g., hip and shoulder).

Fixed joints

Joints that do not allow any movement (e.g., skull).

Antagonistic muscle pairs

Two muscles at a joint that work opposite to enable bending and straightening (e.g., biceps and triceps).

Biceps

Front upper-arm muscle; contracts to bend the elbow.

Triceps

Back upper-arm muscle; contracts to straighten the elbow.

Observing cells

The process of looking at cells carefully with a microscope.

Microscope

Device that magnifies small objects using lenses.

Magnification

Total magnification from eyepiece and objective lenses (e.g., 10x × 20x = 200x).