GCSE Biology Paper 1

Accurate

A measurement that is close to the true value

Measurement error

Difference between measured and true value

Anomaly

Value in results that does not represent the pattern

Random error

Cause readings to be spread about the true value

Systematic error

Readings differ from the true value consistently

Zero error

Equipment doesn't go back to zero

Repeatable

Same person could do the experiment again to get the same results

Reproducible

Another person would repeat the experiment to get the same results

Resolution

The smallest change that an instrument can measure

Uncertainty

The interval that the true value lies within

Nucleus

Controls activities of a cell and contains the DNA

Cytoplasm

Where chemical reactions take place

Cell membrane

Allows passage of materials in and out of the cell

Mitochondria

Where aerobic respiration takes place

Chloroplast

Contains chlorophyll where photosynthesis happens to make glucose

Vacuole

Contains cell sap and keeps the cell rigid

Cell wall

Supports the cell and contains cellulose

Not in an animal cell

Chloroplasts, cell wall, vacuole

Ribosomes

Where proteins are made

Light microscope

Lower resolution, less detail and cheaper

Electron microscope

higher resolution, more detail inside cells but expensive

Magnification

image size/real size

1mm

1000 micrometers

1 micrometer

1000 nanometers

Prokaryotes

DNA is circular, no nucleus, smaller e.g. bacteria

Eukaryotes

DNA inside nucleus and larger e.g. animal and plant cells

Diffusion

Passive net movement of particles from an area of high concentration to an area of low concentration

Fast rate of diffusion

Steep concentration gradient, high temperature, short distance, large surface area

Osmosis

Passive net movement of water molecules from an area of high water concentration to an area of low water concentration, via a partially permeable membrane

Active transport

Movement of particles from an area of low concentration to high concentration, using energy

DNA in eukaryotes

Stored in the nucleus in chromosomes

Mitosis

Used for growth and repair

46

Number of chromosomes in a human adult cell

Before mitosis

DNA and organelles duplicate

Mitosis produces

2 genetically identical daughter cells

Mitosis steps

Chromosomes line up, go to opposite ends of cells and cell divides

Meristems

Where mitosis takes place in plants

Clone

Genetically identical organism

Stem cell

Undifferentiated cell that can become any type of cell

Diabetes

Potentially treated using stem cells

Tissues

Group of similar cells working together to carry out a function

Organs

A group of tissues

Enzymes

Biological catalyst that speeds up the rate of a reaction e.g. breaking down food

Villi

Increase surface area of the small intestine

Mitochondria

Are found in the villi to aid active transport

One cell thick walls

Short diffusion distance

Good blood supply

Maintains concentration gradient in the villi or alveoli

Large intestine

Where water is absorbed into the blood

Bile

Neutralises stomach acid and emulsifies fats

Active site

Part of enzyme that the substrate binds to

Denature

Active site of enzyme changes shape at high temperatures

Protease

Catalyses proteins to amino acids

Lipases

Catalyses lipids into fatty acids and glycerol

Amylase

Catalyses starch into glucose

Amylase is made

Salivary glands, pancreas and small intestine

Protease is made

Stomach, pancreas and small intestine

Hydrochloric acid

Inside the stomach to kill bacteria and provide the pH for protease

Benedict's reagent

Turns from blue to red with sugar

Iodine

Turns brown to black with starch

Biruet reagent

Turns blue to purple with protein

Left side of the heart

Thicker because it pumps oxygenated blood to the brain and body

Right side of the heart

Pumps deoxygenated blood to the lungs

Components of the blood

Plasma, white blood cells, red blood cells and platelets

Red blood cells

Contain haemoglobin to carry oxygen

Adaptations of RBCs

Biconcave to increase surface area and no nucleus to fit more haemoglobin

Haemoglobin

Protein that oxygen binds to inside the RBCs

White blood cells

Kill pathogens

Platelets

Allow blood to clot

Plasma

Liquid component of blood that carries carbon dioxide and urea

Capillaries

Carries blood to tissues to deliver oxygen and remove waste

Artey

Carries blood away from the heart

Vein

Carries blood into the heart

Stent

Treats heart disease by keeping artery open

Statin

Drug that lowers cholesterol to reduct the risk of heart disease

Xylem

Transports water and ions up the plannt

Phloem

Transports glucose around the plant by translocation

Translocation

Process that moves glucose through phloem cells to cells that need glucose for respiration

Stomata

Allows gases into leaves and water is lost through this

Causes of transpiration

Evaporation and diffusion

Increases rate of transpiration

High temperatures, low humidity, high wind

Communicable disease

Disease spread from one person to another

Pathogen

A micro-organism that causes a disease e.g. bacteria, virus or fungus

Toxins

Bacteria make you feel ill by releasing these

Viruses

Replicate inside your cells until the cells burst

How pathogens spread

Wair, water, direct contact

Measles

Viral disease spread by droplets. Causes a rash a fever

HIV

Virus spread by sharing bodily fluids that attacks white blood cells

Rose black spot

A fungus that causes black spots to form on plants

Salmonella

Bacterial disease that causes food poisoning

Vector

An organism that spreads a communicable disease without being ill

Agar gel on petri dish or nutrient broth

Contains culture medium with nutrients for growing bacteria

25 degrees

Maximum temperature you can incubate microorganisms in schools

Aspectic technique

Prevents contamination

Aphids

Insect that damages plants and transmits pathogens

Nitrate ions

Needed for protein synthesis

Stunted growth

Symptom of nitrate deficiency

Magnesium ions

Needed to make chlorophyll - lack of causes chlorsis (yellow leaves)

Identifying plant disease

Looking in a gardening manual, send a sample to the lab or testing kit containing monoclonal antibodies

Plant physical barriers

Cellulose cell wall, waxy cuticle, bark, leaf fall

Chemical barrier

Plants release antibacterial chemicals to protect against pathogens