igcse bio

What is reproduction?

The processes that create more organisms.

"In the binomial name ""Panthera Tigris"" which refers to the genus?"

Panthera.

"In the binomial name ""Felis Catus"", which refers to the species?"

Catus

List two unique features of plant cells.

Cell walls made from cellulose and chloroplasts with chlorophyll pigments.

Parallel veins are a characteristic of dicotyledons; True or false?

False.

Monocotyledons have broad leaves; True or false?

False

Monocotyledons only have one cotyledon; True or false?

True.

List features commonly shared among arthropods.

Multiple pairs of jointed legs, a segmented body, an waterproof exoskeleton, invertebrates.

List the four most common arthropod families.

Insects, Arachnids, Crustacea, Myriapods.

List the five most common classes of vertebrates.

Fishes, Amphibians, Reptiles, Birds, Mammals.

Viruses are alive; True or false?

False

Viruses are protected by what?

A protein coat.

What three structures do all cells except prokaryotes contain?

Ribosomes, rough endoplasmic reticulum, and mitochondria.

The mitochondria _____.

Is the powerhouse of the cell, it allows aerobic respiration.

What is the function of a ciliated cell?

To move mucus in the trachea and bronchi.

What is the function of a root hair cell?

To absorb water.

What are the functions of xylem vessels?

Xylem is responsible for the transport of water and mineral ions from the roots to the rest of the plant. The lignified walls of xylem provide support and structural stability.

What is the function of a palisade mesophyll cell?

Perform photosynthesis.

What is the function of nerve cells?

Conduct neural impulses.

What is the function of red blood cells?

Transport oxygen.

What is the function of sperm and egg cells?

Reproduction.

Define tissue.

A group of cells working together to perform a shared function.

Define organ.

A structure made of tissues working together to perform specific functions.

Define organ system.

GROUPS OF ORGANS WITH RELATED FUNCTIONS, WORKING TOGETHER TO PERFORM BODY FUNCTIONS

1mm = ? micrometers (μm)

1000 micrometers (μm)

If a cell is 5mm long at 100x magnification, how long is it in reality? Give your answer in micrometers (μm).

50 micrometers (μm).

What is diffusion?

Random movement of particles from a higher concentration to a lower concentration, down the concentration gradient.

What is necessary for selective diffusion?

A semi-permeable membrane.

List four factors that affect diffusion.

Surface area, temperature, concentration gradients, and distance.

What is osmosis?

Movement of water molecules from higher water potential to lower water potential through a partially permeable membrane, down the concentration gradient.

What is plasmolysis?

When a cell loses water in a hypertonic solution.

Define turgor pressure.

the pressure of the cytoplasm pushing against the cell wall

Define turgid.

Swollen due to liquid.

Define flaccid.

Lacking firmness.

Why does water diffuse by osmosis into a root hair cell?

Because the water potential inside the cell is lower than outside the cell.

Define hypertonic.

Higher solute concentration compared to another solution across a partially permeable membrane.

Define hypotonic.

Lower solute concentration compared to another solution across a partially permeable membrane.

Define isotonic.

Isotonic means a solution has the same water potential as another, resulting in no net movement of water and maintaining cell shape.

What is active transport?

The movement of particles through a cell membrane from a region of their lower concentration to a region of higher concentration (i.e. against a concentration gradient), using energy from respiration

What two things are necessary for active transport?

Carrier proteins and energy.

Carbohydrates are composed of ____.

Many small sugar units.

Fats and oils are composed of ____.

Glycerol and three fatty acid molecules.

Starch, Glycogen, and Cellulose are all composed of  ____.

Glucose.

What test is used to detect starch and what colour is a positive result?

Iodine solution, blue-black.

What test is used to detect reducing sugars and what colour is a positive result?

Benedict's reagent, orange.

What step is necessary to test for reducing sugars?

Boil the solution after adding the Benedict's reagent.

What is used to test for proteins and what colour is a positive result?

Biuret's reagent, purple/mauve.

What solvent is used to dissolve oils and fats in the emulsion test?

Ethanol.

What step comes after adding the solvent in the emulsion test?

Pour into distilled water.

What colour is a positive result for the emulsion test?

Milky-white.

What test is used to test for vitamin C and what indicates a positive result?

DCPIP, it becomes colourless.

How are different proteins made?

With different combinations of amino acids.

What structure is necessary for the function of enzymes?

The active site.

What structure is necessary for the function of antibodies?

The binding site.

What is the structure of DNA?

Two strands coiled together in a double helix.

What are the letters that represent the four bases?

G,C,A,T.

What base will G bind to?

C.

What base will T bind to?

A.

How are DNA strands connected?

Base pairs.

Define catalyst.

A substance that increases rate of reaction but is not changed by the reaction.

What is an enzyme?

A biological catalyst, composed of proteins.

What is an enzyme-substrate complex?

A temporary combination of the enzyme and substrate used to form a product that can not bind with the enzyme again.

An enzyme can have multiple types of substrates; True or false?

False.

How does a small decrease in temperature from optimal change how an enzyme reacts?

It will react slower since it will not move around and collide as frequently.

How does a large increase in temperature from optimal change how an enzyme reacts?

It will be denatured and no longer function.

How does a large decrease in temperature from optimal change how an enzyme reacts?

It will not function, as there is not enough energy to perform a reaction.

Why are enzymes so useful?

They reduce the activation energy of a reaction that is useful to the body.

Why will a large change in pH denature an enzyme?

The 3D structure of an enzyme is reliant on hydrogen, so adding/removing hydrogen will change the shape of it's active site and denature it.

Define photosynthesis?

The process by which plants manufacture carbohydrates from raw materials using energy from light.

Give the balanced chemical equation for photosynthesis.

6CO2 + 6H2O -> C6H12O6 + 6O2

How is chlorophyll useful for photosynthesis?

It transfers light energy into chemical energy.

How does a greenhouse help grow plants in colder countries?

It allows light energy in and traps heat energy inside.

What colour change represents acidic concentrations of carbon dioxide when using hydrogencarbonate indicator?

Red to yellow.

What colour change represents basic concentrations of carbon dioxide when using hydrogencarbonate indicator?

Red to magenta.

Why are leaves flat?

It creates a large surface area for diffusion and sunlight.

Why are leaves thin?

The create a small distance for diffusion of gases.

Why are there large empty spaces inside a leaf?

To provide an easy passage for carbon dioxide and oxygen.

Why are there so many stomata?

To allow more gas exchange of carbon dioxide and oxygen.

Why are there more chloroplasts in the palisade mesophyll cells than in the spongy mesophyll cells?

Light hits the palisade mesophyll more often and in higher concentrations than the spongy mesophyll cells.

What is the main use of nitrate ions in a plant?

Synthesis of amino acids.

What is the main use of magnesium ions in a plant?

Synthesis of chlorophyll.

How does a deficiency of nitrate ions affect a plant?

It will have stunted growth, the stem will become weak and the leaves will die.

How does a deficiency of magnesium ions affect a plant?

It will turn yellow from the bottom of the stem and continue upwards as chlorophyll requires magnesium.

What can low fiber intake cause?

Constipation.

What can high cholesterol in the blood cause?

Coronary heart disease (CHD).

What can a too-large intake of calories cause?

Obesity.

What can vitamin C deficiency cause?

Scurvy.

What are the main sources of carbohydrates in a healthy diet, and what are they used for?

Whole grains and starchy vegetables, they are dense energy stores that we can break down and store again.

What are the main sources of fats in a healthy diet, and what are they used for?

Nuts, seeds, and fatty meats, they are dense stores of energy and can be used to store large amounts of energy in our bodies.

What are the main sources of proteins in a healthy diet, and what are they used for?

Meat, fish and dairy products, they can be broken down into amino acids and used to build the proteins we need instead.

What are the main sources of vitamin C, and what is it used for?

Fruits and vegetables, it is involved in collagen formation, iron absorption, and many other functions.

What are the main sources of vitamin D, and what is it used for?

Mostly from your skin when in the sun and some in foods, it is used in the absorption of many minerals, including calcium.

What are the main sources of calcium in a healthy diet, and what is it used for?

Dairy products, it improves bone health and is necessary for clotting.

What are the main sources of Iron in a healthy diet, and what is it used for?

Eggs and meat, it is a necessary part of haemoglobin, which transports oxygen in your blood.

What is fibre?

Indigestible cellulose.

What can iron deficiency cause?

Anaemia and in extreme cases, death.

What can vitamin D deficiency cause?

It can cause rickets, where the bones lack calcium and become weak.

What causes kwashiorkor and what are its symptoms?

Protein deficiency, it causes loss of muscle mass, swelling, and more.

What causes marasmus and what are it's symptoms?

Deficiency of all nutrients, it causes stunted growth, intellectual disability, and more.

What is ingestion?

Taking substances into the body via the mouth.