Biology Practice Flashcards

A comprehensive set of practice flashcards covering plant biology (photosynthesis, leaf structure), energy (respiration), ecology (food chains, webs, biodiversity), and inheritance (DNA, variation, evolution) based on the provided lecture notes.

What process do plants use to produce their own food?

Photosynthesis

What is the pigment that absorbs sunlight inside the leaf?

Chlorophyll

Which sub-cellular structures in a plant cell carry out photosynthesis?

Chloroplasts

What is the word equation for photosynthesis?

$$\text{carbon dioxide} + \text{water} \rightarrow \text{oxygen} + \text{glucose}$$

What gas is produced during photosynthesis?

Oxygen

What are the two reactants involved in photosynthesis?

Carbon dioxide and water

What are the two products involved in photosynthesis?

Oxygen and glucose

Give three uses for glucose in a plant.

Respiration, making cell walls and converting to starch for storage

What substance is used to test for the presence of starch?

Iodine

Name three adaptations of a leaf.

Large surface area, thin and contains chlorophyll

Explain why leaves have large surface areas.

To absorb more sunlight

Explain why leaves are thin.

To give a short diffusion pathway

Explain why leaves have chlorophyll.

To absorb sunlight for photosynthesis

Name the five layers of a leaf.

Waxy cuticle, upper epidermis, palisade mesophyll layer, spongy mesophyll layer and lower epidermis

What are stomata?

Small gaps on the bottom of leaves

In which layer of a leaf are the stomata found?

Lower epidermis

What is the function of the stomata?

To allow oxygen to leave and carbon dioxide to enter the leaf

What are the guard cells?

Curved cells found on the bottom of leaves

What is the function of the guard cells?

To open and close the stomata

What is the waxy cuticle?

A thin layer found on the top surface of the leaf

What is the function of the waxy cuticle?

To stop water loss from the leaves

Name an adaptation of the palisade mesophyll cells.

Contain lots of chloroplasts

Explain why palisade mesophyll cells have lots of chloroplasts.

To absorb more sunlight for photosynthesis

What is the purpose of the air spaces in leaves?

To allow gases to diffuse in and out of the leaf

Why do all cells respire?

So they can get energy to function

What is the word equation for aerobic respiration?

$$\text{glucose} + \text{oxygen} \rightarrow \text{carbon dioxide} + \text{water}$$

What do we call the reaction that releases energy from glucose?

Aerobic respiration

Why is 'energy' not in the equation for respiration?

Because it is not a chemical substance

What are the reactants involved in aerobic respiration?

Glucose and oxygen

What are the products involved in aerobic respiration?

Carbon dioxide and water

Which sub-cellular structures are responsible for respiration?

Mitochondria

What is the advantage of aerobic respiration compared with anaerobic respiration?

It releases more energy

Which type of respiration does not need oxygen?

Anaerobic respiration

What is the product of anaerobic respiration in animals?

Lactic acid

What are the products of anaerobic respiration in yeast?

Ethanol and carbon dioxide

What is the reactant involved in anaerobic respiration?

Glucose

What is fermentation?

Anaerobic respiration in yeast or bacteria

What is the word equation for anaerobic respiration in humans?

$$\text{glucose} \rightarrow \text{lactic acid}$$

What is the word equation for anaerobic respiration in yeast?

$$\text{glucose} \rightarrow \text{ethanol} + \text{carbon dioxide}$$

What is the advantage of anaerobic respiration compared with aerobic respiration?

It is able to happen when there is not enough oxygen for aerobic respiration

What is a feeding relationship?

Which organisms eat each other

Why do organisms eat each other?

To get nutrients and energy

What diagrams do scientists use to show feeding relationships?

Food chains

What name is given to organisms that make their own food?

Producers

Where do producers get their energy from?

The Sun

In a food chain, what name is given to an organism that eats another organism?

Consumer

In a food chain, which direction do the arrows point?

From the organism being eaten to the organism eating it

In a food chain or web, why do the arrows point from the organism being eaten to the organism eating it?

To show the flow of energy

What is bioaccumulation?

How toxic materials can build up in a food chain

What is interdependence?

How organisms depend on each other for survival

What is a food web?

A group of interconnected food chains

What name is given to organisms that eat animals?

Predators

What name is given to animals that are eaten by other organisms?

Prey

What happens to the number of prey if the number of predators increases?

The number of prey decreases as more are eaten

What happens to the number of predators if the number of prey decreases?

The number of predators decreases as they starve

What is a herbivore?

An animal that eats plants

What is a carnivore?

An animal that eats other animals

What is an omnivore?

An animal that eats plants and animals

What is the 'population' of an organism?

The number of that organism in a particular area

What is an adaptation?

A way in which an organism suits its environment

Why do polar bears have white fur?

Camouflage, so they can hunt prey

What adaptations does a polar bear have to stay warm in the Arctic?

Body fat, lots of fur and thick legs

What adaptations does a camel have to help it stay cool in the desert?

Thin legs, short hair

What is the purpose of a camel's hump of fat?

To release energy and make water

Why do camels have long eyelashes?

To stop the sand going in their eyes

How is a cactus adapted to prevent water loss?

Thick waxy layer and swollen stem instead of leaves

Why does a cactus have spines?

To stop it being eaten

Why does a cactus have shallow but wide roots?

To absorb as much rainwater as possible

Why does a cactus have a succulent stem instead of leaves?

To prevent water loss

What happens during insect pollination?

An insect carries pollen from one flower to another

What is the consequence of insect pollination?

Fertilisation of the ovum by the pollen

Why do insects fly from flower to flower?

They are attracted to the flowers' colour and nectar

What can happen to a flower once it is pollinated?

It grows a fruit or seed

Which insects are the most common pollinators?

Bees

What are the two factors causing bee numbers to drop?

Use of pesticides and loss of habitat

What is the relationship between the number of bees and the number of flowers that can be pollinated?

As the number of bees reduces, the number of flowers pollinated will reduce

What is food security?

The ability of all people to have enough food all the time

What is a pesticide?

A chemical that kills crop-eating insects

Give three ways to help increase bee numbers.

Do not spray pesticides, Plant more flowers, Let grass grow long

What is heredity?

The process by which genetic information is transmitted from one generation to another

What is DNA?

A genetic code

Where is DNA found in a cell?

In the nucleus

What is a chromosome?

Long chain of coiled DNA

What is a gene?

A section of DNA coding for a protein

Name the scientists who collectively discovered the structure of DNA.

Francis Crick, James Watson, Maurice Wilkins and Rosalind Franklin

In biology, what is variation?

Differences between organisms

What is genetic variation?

Differences caused by DNA

What is environmental variation?

Differences caused by the environment

State two examples of genetic variation in humans.

Eye colour and ear lobe shape

State two examples of environmental variation in humans.

Scars and tattoos

State two examples of variation caused by environmental and genetic variation.

Height, the foods a person likes to eat

Some variation can show a range of differences, like height. What name is given to this type of variation?

Continuous variation

Give two other examples of continuous variation.

Skin colour, weight

Some variation is limited to a number of categories, like shoe size or eye colour. What name is given to this type of variation?

Discontinuous variation

Give two other examples of discontinuous variation.

Blood group, tongue rolling

Why are we not genetically identical to our parents?

We inherit half of our DNA from each parent

What do animals compete with each other for?

Food, mates, territory

What do plants compete with each other for?

Light, water, minerals, space

What is an adaptation?

A feature that enables an organism to survive

Darwin's theory of evolution occurs through which process?

Natural selection