Unit 1: The Nature and Variety of Organisms

Question 1

What are the the eight basic characteristics all living organisms have

Answer 1

Nutrition, Respiration, Excretion, Response/Sensitivity, Movement, Control, Reproduction, Growth/Development

Question 2

Why do they need nutrition

Answer 2

To be provided with energy and the raw materials for growth and repair

Question 3

What is respiration

Answer 3

The transfer of energy from glucose, this process goes on in every cell of your body

Question 4

What is excretion and give examples

Answer 4

Excretion is the removal of waste products from the body.
.CO2 is a waste product from the lungs
.Sweat is a waste product from the skin
.Excretion is also carried out by the kidneys

Question 5

What is response

Answer 5

Living organisms can react to changes in their surroundings

Question 6

What is movement

Answer 6

Moving towards things such as water and food, and away from things such as predators and poisons.

Question 7

What is control

Answer 7

Balancing body functions to maintain a “constant internal environment”(homeostasis)

Question 8

What is reproduction

Answer 8

Organisms passing on their genes to offsprings

Question 9

What is growth and development

Answer 9

Increasing in size and mass using materials from food

Question 10

What are living organisms made of

Answer 10

Cells

Question 11

What are eukaryotic cells

Answer 11

Complex cell structures

Question 12

Two examples of eukaryotic cells

Answer 12

.Animal cells
.Plant cells
.Fungi

Question 13

What are prokaryotic cells

Answer 13

Simple, small structured cells

Question 14

Two examples of prokaryotic cells

Answer 14

.Protoctists
.Bacteria
.Viruses

Question 15

Explain 3 features in an animal cell

Answer 15

Nucleus: An organelle that contains DNA that controls the cells activities and is surrounded by its own membrane.
Cell membrane: Forms on the outer surface of the cell and controls the substances that go in and out.
Cytoplasm: A gel-like substance where most of the cells chemical reactions take place. It contains enzymes that control these reactions.
Mitochondria: Small organelles where most of the reactions for aerobic respiration take place.
Ribosomes: Small organelles where proteins are made in the cell

Question 16

Explain 3 features in plant cells that are not found in animal cells

Answer 16

Chloroplast: Contains chlorophyll, the pigment used to absorb sunlight for photosynthesis
Cell wall: A rigid structure made of cellulose, which surrounds the cell membrane. It supports and strengthens the cell
Vacuole: A large organelle that contains cell sap that helps to support the cell

Question 17

What are fungi

Answer 17

.Some are single-celled while others have a body called a mycelium that is made up of hyphae.
.They can’t photosynthesize
.They have cell walls made of chitin
.Most are fed by saprotrophic nutrition.
They can store carbohydrates as glycogen

Hyphae: A thread like structure that contains lots of nuclei

Saprotrophic nutrition: They secrete extracellular enzymes into the area outside their body to dissolve their food, so they can then absorbe the nutrients.

Question 18

One example of a single celled fungus and one example of a multicellular fungus

Answer 18

.Yeast: Single-celled fungus
.Mucor: A multicellullar fungus with a mycelium and hyphae

Question 19

What are protoctists

Answer 19

.They are single celled and microscopic
.Some have chloroplasts and are similar to plant cells
.Others are similar to animal cells

Question 20

Give a similarity each protoctists have to plant cells and animal cells and give two examples

Answer 20

.Amoeba(Animal cells): Does not have a cell wall and is free to move
.Chlorella(Plant cells): Contains chlorophyll

Amoeba: A cell that lives in pond water
Chlorella: A plant like cell

Question 21

What is bacteria

Answer 21

.Single celled microscopic organisms
.They don’t have a nucleus
.They don’t have a circular chromosome of DNA
.Some can photosynthesize
.Most bacteria feed off other organisms, both living and dead

Question 22

What similarities and differences do bacterium have with animal cells and/or plant cells

Answer 22

.Difference:
-Bacterium have no nucleus
-Don’t have a circular chromosone of DNA
-Feed off other organisms

Similarity:
-Some can photosynthesis
-Have a cell wall
-Have cytoplasm

Question 23

What are viruses

Answer 23

.These are particles rather than cells and are smaller than bacteria
. They can only reproduce inside living cells
.They infect all types of living organisms
.They come in many different sizes and shapes
.They don’t have a cellular structure- They have a protein coat around some genetic material (either RNA or DNA)

A virus is a parasite, it depends on other organisms to grow/produce

Question 24

What features make a virus different from most organisms

Answer 24

.They are particles rather than cells
.They depend on another organism to grow and reproduce
. Does not have a nucleus

Question 25

What are pathogens

Answer 25

Pathogens are organisms that cause diseases

Question 26

Examples of pathogens

Answer 26

Protoctists: Plasmodium, which causes malaria
Bacterium: Pneumococcus, which causes pneumonia
Viruses:
-Influenza virus which causes flu
-HIV whic causes AIDS

Question 27

What are enzymes

Answer 27

Enzymes are biological catalysts that increase the speed of reactions in the body

Catalyst: Increate the rate of reaction without being changed or used

Question 28

How do enzymes help the body

Answer 28

Enzymes reduce the need for high temperatures, as well as speeding metabolic reactions

Question 29

What are enzymes made of

Answer 29

Enzymes are made of proteins, and all proteins are made of chains of amino acids.

Question 30

Explain the process of enzymes

Answer 30

.Chemical reactions involve things either being split apart or joined together
. A substrate is a molecule that is changed in a reaction
.Every enzyme molecule has an active site
.Every enzyme only speeds up one reaction, this is because for the enzyme to work a substrate has to be the perfect shape to fit into the active site

Active site: Where a substrate joins onto an enzyme

Question 31

What two environmental features affect enzymes

Answer 31

Temperature and pH

Question 32

How does temperature affect enzyme function

Answer 32

.Change in temperature affects the rate of enzyme-catalyste reactions
.As temperature increases the enzymes and substrates have more energy, causing them to move around more and are then more likely to collide and form enzyme-substrate complexes
.The optimal temperature is the temperature where enzymes are most active
.If the temperature goes above the optimal temperature the active site of the enzymes will become denatured, meaning the substrates no longer fit into the active site.

Question 33

How does pH affect enzyme function

Answer 33

If the pH is too high or too low the enzymes active site can also become denatured

Question 34

What is diffusion

Answer 34

The movement of particles from an area of high concentration to an area of low concentration until equilibrium is reached

Question 35

What is osmosis

Answer 35

Osmosis is the net movement of water molecules from an area of high water concentration to an area of low water concentration across a partially permiable membrane until equilibrium is reached

Question 36

What is active transport

Answer 36

The movement of particles from an area of low concentration to an area of high concentration