Biology Gcse revision

Living organism Characteristics

1. Movement

2. Nutrition

3. Respiration

4. Reproduction

5. Excretion

6. Growth

7. Homeostasis

8. Sensitivity

Word equation for aerobic respiration

Glucose + oxygen —> Carbon dioxide + water

Excretion definition

The removal of toxic metabolic materials and substances from organisms

Sensitivity in plants

Geo and phototropism

Examples of eukaryotic organisms

1. Protoctista

2. Fungi

3. Plants

4. Animals

Eukaryotes characteristics

1. Can be both single and multicellular

2. Contain a nucleus

3. Have a distinct membrane

Prokaryotes characteristics

1. Single called

2. No nucleus

3. The nuclear material is found in the cytoplasm

Prokaryote example

Bacteria

1.Lactobacillus

Pneumococcus

Pathogens

1. Bacteria

2. Fungi

3. Protoctist

4. Viruses

Why are viruses no classified as living organisms

1. Need a host cell to reproduce

2. Smaller than bacteria

3. No cellular structure

4. Contain either dna or rna

Level of organization in organisms

Organelle → Cell → Tissue → Organ → Organ System → Organism

3 tissues in plants

1. Xylem

2. Phloem

3. Mesophylls

Ribosome definition

Site of protein synthesis

Vacuole definition

1. Contains cell sap

2. Supports the shape

3. Used for storage of certain materials

Differences between plant and animal cells

1. Cell wall

2. Chloroplasts

3. Permanent vacuole

Cell differentiation meaning

How cells develop the structure and characteristics needed to carry out their functions

Specialized cell definition

Cells that have gone through cell differentiation

How are RBC specialties to carry out their functions

Biconcave shape Large SA

Contain haemoglobin

What are undifferentiated cells called

Stem cells

Types of stem cells

1. Embryonic (embryo) any type of cell

2. Adult (bone marrow, skin) cells of the blood

Elements in proteins

Carbon, oxygen, hydrogen, nitrogen

Positive color change of starch

Orange to blue / black

Positive color change for protein

Blue to violet / purple

Corms meaning

Change - the independent variable

Organism - organism being used

Repeat - carried out for reliable results

Measurement 1 - how will you measure your dependent variable

Measurement 2 - what time scale will you use

Same - what will you control

Same

Biological catalyst

They speed up the chemical reactions within the body without being used up

What happens to enzymes when their shape changes

They denature

Diffusion definition

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

Osmosis def

The net movement of water molecules form an area of high to low water potential through a partially permeable membrane

Active transport def

The movement of particles from low to high concentration across a cell membrane and requires atp

Factors affecting the movement of substances

1. Surface area

2. Diffusion distance

3. Temperature

4. Concentration gradient

Photosynthesis equation

Carbon dioxide + Water → glucose + oxygen

Glucose uses in plants

1. Produce starch for storage

2. Synthesise lipids

3. To form cellulose for cell walls

4. To produce amino acids

Limiting factors

1. Temperature

2. Light intensity

3. Carbon Dioxide concentration

Adaptations of the leaf

1. Large SA for diffusion and light absorption

2. Thin short diffusion distance for Carbon Dioxide

3. Many chlorophyll to absorb light

4. Stomata allow CO2 to diffuse in and oxygen out

5. Epidermis is transparent to let light through

6. Palisade layer has many chlorophyll for light

7. Spongy mesophyll has airspace’s for CO2 increasing the surface area

Both Mineral ions and their functions

1. Magnesium - needed to produce chlorophyll ( lack will cause yellow leaves)

2. Nitrogen - needed to produce amino acids ( lack will cause stunted growth)

Why is vitamin D required

To absorb calcium and is required for strong teeth and bones

Why is vitamin A required

Needed to make pigment in the retina

Why is iron required

Needed to produce hemoglobin that helps to carry oxygen

Where is bile produced

Liver

What happens in the small intestine

1. Duodenum - digestion of food exiting the stomach by enzymes

2. Ph is around 8 - 9 so it is slightly alkaline

3. Ileum - absorption of water and digested food molecules

4. Lined with vili

Peristalsis def

It helps move food along the alimentary canal by wave like contractions

Role of enzymes in digestion

Break down large, insoluble molecules into smaller, soluble molecules that can be absorbed into the blood stream

Stages of starch and the enzyme that breaks it down

Amylase, Maltese

Starch ( amylase ) → Maltose ( Maltase ) → Glucose

What are lipids made up of

1 glycerol and 3 fatty acids

Bile usages

1. Neutralizes the acid from the stomach so that it is the optimum ph for the enzymes in the SI

2. Emulsifies lipids ( breaking apart large droplets into smaller ones increasing the surface area

Small intestine adaptations

1. Large surface area because of the villi made up of many microvilli for absorption

2. The villus is one cell thick for a short diffusion distance

3. Steep concentration gradient

ATP usages

1. Chemical reactions

2. Muscle contractions

3. Keeping warm

Anaerobic respiration word equation

Glucose → Lactic Acid

What happens in terms of Oxygen and Carbon Dioxide during photosynthesis

Carbon dioxide moves into the leaf

Oxygen moves out of the leaf

What happens in terms of Oxygen and Carbon Dioxide during respiration in the leaf

Carbon dioxide moves out of the leaf

Oxygen moves into the leaf

The difference in gas exchange during night and day

DAY:

Rate of photosynthesis > respiration

Night:

Rate of photosynthesis < respiration

What color will the hydrogen carbonate indicator change to

Yellow if there is a high CO2

Purple if there is a high concentration of CO2

Orange if the rate of photosynthesis is equal to the rate of respiration