2. Life On Earth

Question 1

Abomasum

Answer 1

The fourth and final section of the stomach in ruminants, were food is digested by acid and enzymes.

Question 2

Absorption

Answer 2

The taking in of a substance, usually a liquid.

Question 3

Aerobic

Answer 3

Living or active in the presence of oxygen.

Question 4

Amino acids

Answer 4

Organic compounds which are the building blocks of proteins. There are about 20 essential amino acids in humans that we have to take in.

Question 5

Anaerobic

Answer 5

The absence of oxygen.

Question 6

Archaea

Answer 6

Archaea are procaryotic ‘primitive’ cells that are not bacteria and have an unusual chemistry. Many live in extreme environments like hot springs or acidic lakes.

Question 7

Asexual Reproduction

Answer 7

The production of a new organism without gametes. It can involve spores or simple division.

Question 8

Autotrophs

Answer 8

Organisms that make their own food from inorganic components such as plants.

Question 9

Bacteria

Answer 9

Unicellular procaryotic organisms usually between 0.5 and 5 micrometres. Bacteria have cell walls made of different biochemicals to those found in plants and archaea.

Question 10

Biochemicals

Answer 10

Chemicals found in or associated with living things.

Question 11

Robert Brown

Answer 11

The first scientist to describe the nucleus of a cell.

Question 12

Carnivore

Answer 12

An animal which eats other animals.

Question 13

Cell Division

Answer 13

The process by which cells form daughter cells. It consists if mitosis and cytokinesis.

Question 14

Cell Membrane

Answer 14

A layer that separates the cell from its environment and controls the passage of materials into and out of the cell.

Question 15

Cell Wall

Answer 15

A structure outside the cell membrane and occurs in plants and fungi. It provides support and contains cellulose, pectin and lignin.

Question 16

Chloride Ion

Answer 16

An atom with an extra electron which makes it a negatively charged particle - an electrolyte; it is found in cells and is important in cellular activity.

Question 17

Chlorophyll

Answer 17

The green pigment in plants associated with the capture of sunlight for use in photosynthesis.

Question 18

Chloroplast

Answer 18

A green organelle or plastid in plants responsible for photosynthesis.

Question 19

Chromosomes

Answer 19

Thread-like bodies that appear in cell division and are responsible for transmitting genetic information.

Question 20

Circulatory System

Answer 20

The organ system consisting of the heart, arteries, veins, capillaries and blood in vertebrates and is responsible for the transport of oxygen, nutrients and wastes around the body.

Question 21

Colonial Organisms

Answer 21

Organisms consisting of a loose aggregation of sllghtly specialised cells that re-aggregate if disturbed.

Question 22

Concentration

Answer 22

Concentration is the amount of a substance - often relative to the amount of solute in a solution - and can be expressed as a percentage or g/L and so on.

Question 23

Cuticle

Answer 23

Cuticle is the protective wax outer covering of a leaf or the flexible outer surface of some invertebrates made if chitin.

Question 24

Cyanobacteria

Answer 24

Cyanobacteria (one called blue-green algae) are procaryote cells that carry out photosynthesis and represent one of the most primitive groups of living things.

Question 25

Cytokinesis

Answer 25

Cytokinesis is the final stage of cell division involving the redistribution of the cytoplasm between daughter cells.

Question 26

Cytoplasm

Answer 26

The contents of the cell membrane excluding the nucleus. It includes the transparent liquid, cytosol and organelles. It is the site of most of the chemical activities that occur in the cell.

Question 27

Daughter Cells

Answer 27

Daughter cells are the products of cell division.

Question 28

Dermis

Answer 28

Dermis is a type of tissue that provides the external covering layer of plants. Also the layer below the epidermis in vertebrates.

Question 29

Differentiation

Answer 29

Differentiation refers to the changes that occur in development and result in a cell becoming specialised in structure and function.

Question 30

Diffusion

Answer 30

Diffusion is the movement of material (usually fluids) from places of high concentration to places of lower concentration until the solution is evenly mixed.

Question 31

Digestive Chemicals

Answer 31

Digestive chemicals are substances (enzymes) that break complex molecules into simpler ones.

Question 32

Diverticulum

Answer 32

Diverticulum is a specialised branch of the stomach in nectar feeders which stores nectar.

Question 33

DNA

Answer 33

DNA is deoxyribonucleic acid, the large organic molecule (nucleic acid) responsible for storing hereditary information in living things, and is found on chromosomes.

Question 34

Endoplasmic Reticulum

Answer 34

Endoplasmic reticulum is a double membrane that forms a convoluted network of tubes that connects the cell membrane to the nucleus.

Question 35

Epidermal Cells

Answer 35

Epidermal cells (plant) are cells that provide the outermost protective layer on plant structures such as leaves.

Question 36

Epithelial Tissue

Answer 36

Epithelial tissue makes up the surface of the body and organs. It serves the functions of protection and/or secretion, absorption and sensation.

Question 37

Eubacteria

Answer 37

Eubacteria (or bacteria) were once called 'true bacteria' and are distinguished on the basis of shape. They are widespread and some cause disease while others are essential for our well-being.

Question 38

Eucaryotic Cells

Answer 38

Eucaryotic cells are cells that contain a nucleus and organelles and genetic material borne on chromosomes.

Question 39

Exchange

Answer 39

To give up and receive or replace.

Question 40

Excretory System

Answer 40

Excretory system is the system of organs with the function of removing wastes from the organism.

Question 41

Freeze Fracture

Answer 41

A method for preparing specimens for the electron microscope involving rapid freezing followed by splitting. It is a useful method for investigating at the internal structure of membranes.

Question 42

Glucose

Answer 42

Glucose is a simple monosaccharide sugar, commonly produced by digestion of more complex carbohydrates (and other compounds) in animals, and is a product of photosynthesis in plants. It is the major reactant in respiration.