Biology Shell Summer Exam

Characteristics of living things

MRS H GREN

Plants

Multicellular organisms

They have chloroplasts and cellulose cell walls

They carry out photosynthesis

They store carbohydrates as starch or sucrose

Examples include maize, peas and beans.

Animals

Multicellular organisms

No chloroplasts, cell walls or photosynthesis

They store carbohydrate as glycogen

Animals include humans, houseflies and mosquitoes.

Fungi

Some are single celled

No photosynthesis but chitin cell walls

Made from mycelium which is made from hyphae (contain many nuclei)

They use saprotrophic nutrition

carbohydrate stored as glycogen

Examples include mucor and yeast.

Protoctists

Microscopic single-celled organisms

Some resemble plant structured cells and others animals

Examples are chlorella and plasmodium

Bacteria

Microscopic single-celled organisms

Have cell wall and membrane

No nucleus but some carry out photosynthesis

Example includes lactobacillus and pneumococcus (causes pneumonia)

Pathogen

An organism causing disease (fungi, bacteria, protoctist or virus)

Viruses

They are small non-living organisms

No cellular structure

Only reproduce inside living cells

Examples include tobacco mosaic virus causing leaf discolouring and HIV causing AIDS

Level of organisation in organsims

Organelle, cell, tissue, organ, system.

Differences between plant and animal cells.

Plants have cell walls, chloroplasts and a vacuole, whereas animal cells do not.

Nucleus

A part of the cell containing DNA and responsible for growth and reproduction.

Cytoplasm

A fluid inside the cell which protects the organelles within.

Cell membrane

A cell structure that controls which substances can enter or leave the cell.

Cell wall

A structure that surrounds the cell membrane and provides support to the cell.

Mitochondria

Powerhouse of the cell, organelle that is the site of energy production.

Chloroplasts

Capture energy from sunlight and use it to produce food for the cell

Ribosomes

Makes proteins (protein synthesis).

Vacuole

A sac inside a cell that acts as a storage area

Elements in carbohydrates

Carbon, hydrogen, oxygen

Elements in proteins

Carbon, hydrogen, oxygen, nitrogen

Elements in lipids

Carbon, hydrogen, oxygen

Structure of starch

long chain of glucose molecules

Structure of protein

Long chain of amino acids

Enzymes role

Increase the rate of reaction by lowering the activation energy without being used up themselves.

Photosynthesis word equation

carbon dioxide + water --> glucose + oxygen

Photosynthesis balanced symbol equation

6CO2 + 6H2O --> C6H12O6 + 6O2

Structure of a leaf

Waxy cuticle - reduces water losss

Upper epidermis - transparent to allow light through

Palisade layer - contains most chloroplasts

Spongy layer

Lower epidermis

Guard cells around stomata - lets CO2 diffuse

Required Ions

Plants require mineral ions for growth

Magnesium ions are needed for chlorophyll

Nitrate ions are needed for amino acids

Effects on the rate of photosynthesis

Carbon dioxide concentration, light intensity and temperature

How do glasshouses and polythene tunnels increase crop yield?

They keep them away from pests and diseases in a controlled environment so that efficiency can be maximised.

How do fertilisers increase crop yield?

Fertilisers provide nutrients for the plant

which are needed for growth.

Advantages of pest control

-Quick and efficient

-Crop yield is increased

Disadvantages of pest control

- Expensive

- Environmental damage

- Poisonous to humans and wildlife

- Can cause water pollution

What is fish farming?

It is when fish are farmed and bred in a controlled environment to maximised yield, size and taste.

They can be fed specifically the right food and the water can be monitored.

The water can also be removed and filtered.

Sources of carbohydrates

Pasta, rice, sugar (provides energy)

Sources of proteins

Meat and fish (Growth and repair)

Sources of lipids

Butter and oily fish (energy store and insulation)

Sources of Vitamin A

Liver (Improves vision and skin)

Sources of Vitamin C

Fruit (prevents scurvy)

Sources of Vitamin D

Eggs and sunlight (calcium absorbtion)

Sources of Water

Food and drink (basically every bodily function)

Sources of calcium

Milk and cheese (makes bones and teeth)

Sources of iron

Red meat (healthy blood)

How do energy requirements vary?

They vary with activity levels, age and pregnancy.

Processes food can go through:

ingestion, digestion, absorbtion, assimilation and egestion

What is peristalsis?

The process of circular muscle contractions moving food through the gut

What is the role of digestive enzymes?

They break down large molecules into smaller ones.

Enzyms include amylase, maltase, protease and lipase.

Where is bile produced and stored?

It is produced in the liver and stored in the gallbladder.

What is bile's role in digestion?

It neutralises stomach acids and emulsifies fats to speed up digestion.

How is the small intestine adapted for absorption?

It is long, has a large surface area and a layer of permeable cells with a good blood supply.

What does a balanced diet include?

A balanced amount of carbohydrates, proteins, lipids, vitamins, minerals and water.

Structure of the alimentary canal:

- mouth (breaks down food)

- oesophagus (connects mouth and stomach)

-stomach (pummels food and produces enzymes)

-small intestine (produces enzymes and absorbs nutrients)

-large intestine (excess water is absorbed)

-pancreas (produces enzyme)

Structure of an insect pollination plant

They are sticky, brightly coloured and scented.

Structure of an wind pollination plant

Small, dull, scentless petals.

Long filaments and lots of pollen to be carried away by the wind.

Conditions needed for seed germination

water, oxygen, warmth

What do germinating seeds utilize before they can carry out photosynthesis?

Food reserves

Population

All the different organisms of one species in a habitat.

Habitat

The place where an organism lives.

Community

All the different species living in a habitat.

Ecosystem

All the different organisms living in a particular area and all the non-living abiotic conditions.

Biodiversity

The variety of different species of organisms on Earth, or within an ecosystem.

Biotic factors:

-Availability of food

-Number of predators

-Competition

Abiotic factors:

-Environmental conditions

-Toxic chemicals

What can biodiversity be measured using?

Quadrats

What equation would you use?

Mean= total number of organsims/number of quadrats

Trophic level names:

-producer

-primary consumer

-secondary consumer

-tertiary consumer

-decomposers

How much energy is transferred from one trophic level to the next?

10%

REMEMBER WHEN DESCRIBING PRACTICALS

Compare

Organism

Repeat

Measure (unit and time)

Same (give 2)