BIOLOGY - topic 2-3.3.3 definitions

definitions

Taxonomy

the branch of biology concerned with identifying, naming, and classifying species into groups called taxa.

taxa

are the general name of groups within a classification system

classification

process of grouping organisms according to structural similarities

hierarchical classification system

these groups are arranged from the largest group of organisms to the smallest group of organisms which they never overlap

species

a group of organisms with similar features and these organisms are capable of breeding & producing a fertile offspring

binomial system

system used to identify a specific type of organism using 2 world Latin name [ genus capitalised + species - never capitalised ] .

microscope

an apparatus used to enlarge very small objects that cannot be seen with a naked eye

biological system

a small sample of a part taken to show the nature of the whole for microscope studies

magnification

the number of times an object is increased by lens system

cell

the smallest biological unit that possess all the characteristics of a living organism

organelle

is a tiny cellular structure that performs specific functions within a cell

Endoplasmic Reticulum

A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another.

Ribosomes

site of protein synthesis and are produced by Golgi bodies. Hey are vey small beads of RNA (ribonucleic acid )

Diffusion

movement of molecules, atoms and ions from a region of their higher concentration to a region of their lower concentration down a concentration gradient

surface area in cell

total area of surface of the object

facilitated diffusion

molecules such as oxygen and carbon dioxide diffuse very fast through cell membranes in solution

simple diffusion

passive transport where no energy is required for molecules to move out or into the cell

osmosis

movement of water molecules from high water potential to lower water potential through a partially permeable membrane down a water potential gradient

partially permeable membrane

allows small molecules to pass through but not larger ones

visking tube

cell manufactured membrane that acts like a cell membrane

hypotonic solution

solution that has more free molecules and less solutes than the cell, so water molecules move in the cell e.g. distilled water

isotonic solution

solution where water potential is the same inside and outside of the cell, water will then move across the membrane in both direction maintain cell size

hypertonic solution

solution that has higher solute concentration and less free water molecules than the cell, hence water molecules will move out of the cell

osmosis facilities

movement of water into and out of the cell

active transport

passage of atoms and molecules from region of low concentration to a region of high concentration against the concentration gradient requiring ATP