B2 SS Flashcards

What is the role of photosynthetic organisms in a food chain?

Producers that produce biomass for the food chain.

What is photosynthesis?

An endothermic reaction to produce glucose.

What is the word equation for photosynthesis?

Carbon dioxide + water → glucose + oxygen.

What are the three limiting factors for photosynthesis?

Carbon dioxide, light, and temperature.

What happens to the rate of photosynthesis as carbon dioxide concentration increases?

It increases up to a point where another factor will become limiting.

What are the independent, dependent, and control variables for the photosynthesis core practical?

Independent - distance of lamp; Dependent - rate of photosynthesis (e.g., number of bubbles); Control - temperature of water.

What equipment is used to measure light intensity?

Light meter or light lux.

What chemical is used to control carbon dioxide levels?

Soda lime or potassium hydroxide.

What are the adaptations of a root hair cell?

Large surface area and thin cell walls allow maximum water and mineral ion absorption.

How do plants uptake nitrates and mineral ions?

Through active transport.

What is transpiration?

The flow of water from the root, up the stem, and out of the leaves.

What is translocation?

Transport of sucrose through phloem tissue.

What is the function of the xylem?

Transports water and minerals using dead cells with rings of lignin to withstand high water pressure.

What is the function of the phloem?

Transports glucose/sucrose using living cells and sieve plates.

What factors increase transpiration?

Wind, increased temperature, and increased light intensity.

What are the roles of oestrogen and progesterone in the menstrual cycle?

Oestrogen builds the uterus lining ready for ovulation; progesterone maintains the uterus lining.

How do hormonal contraception methods prevent pregnancy?

They release hormones to prevent ovulation and thicken mucus at the cervix preventing sperm entry.

What are two barrier methods of contraception?

Condom and diaphragm/cap.

What is homeostasis?

Maintaining a constant internal environment.

Why is homeostasis important?

It helps to prevent damage to the body as internal and external conditions change.

What is the role of insulin in blood glucose control?

It causes liver cells to store glucose as glycogen.

What causes type 1 diabetes and how is it controlled?

Not enough insulin produced; controlled by eating healthy and exercising.

What causes type 2 diabetes and how is it controlled?

Pancreatic cells do not produce insulin; controlled by injecting insulin in the fat layer of skin.

What is the BMI equation?

BMI = mass (kg) / (height (m))².

What substances diffuse into cells for respiration or producing new substances?

Oxygen, glucose, amino acids, and fatty acids.

What substances diffuse out of cells?

Carbon dioxide, urea, and water.

Where does gas exchange take place in the lungs?

In the alveoli.

What are the adaptations of the alveoli for gas exchange?

Large surface area, thin walls, and moist lining.

What is the function of red blood cells?

Carry oxygen

How are red blood cells adapted to their function?

Packed with haemoglobin, biconcave shape, no nucleus

What is the function of white blood cells?

Phagocytes engulf pathogens; lymphocytes produce antibodies

How are white blood cells adapted to their function?

Irregular shape to surround and digest foreign cells

What is the function of plasma?

Carries dissolved substances

How is plasma adapted to its function?

Straw coloured liquid

What is the function of platelets?

Blood clotting

How are platelets adapted to their function?

Tiny fragments, no nuclei

What is the significance of surface area to volume ratio in gas exchange?

Maximizes gas exchange

What is the structure of arteries?

Narrow tube, thick elastic wall

What is the function of arteries?

Take blood away from heart under high pressure

What is the structure of veins?

Wide tube, thin flexible wall, valves prevent backflow

What is the function of veins?

Carry blood back to the heart under low pressure

What is the structure of capillaries?

One cell thick wall

What is the function of capillaries?

Diffusion of substances in tissues

Where are valves found in the body?

In veins and between the atria and ventricles in the heart

What is the equation for cardiac output?

Cardiac output = stroke volume x heart rate

What is cellular respiration?

Exothermic reaction that releases energy from glucose

What is the word equation for aerobic respiration?

Glucose + oxygen → carbon dioxide + water

What is the word equation for anaerobic respiration?

Glucose → lactic acid

What are the differences between aerobic and anaerobic respiration?

Aerobic uses oxygen, produces CO2 and water; anaerobic does not use oxygen, produces lactic acid.

What is mutualism?

Organisms that live together and both benefit from the relationship

Give an example of mutualism.

Oxpecker & ox, flower & insect, algae & coral, bacteria & legumes

What is parasitism?

The parasite benefits by living off and feeding off a host

Give examples of parasites and their hosts.

Head lice and human, tapeworm and human/mammal, mistletoe and tree

What is one advantage of fish farming?

Reduces overfishing of wild fish

What is one disadvantage of fish farming?

Disease spreads easily

What are abiotic factors?

Temperature, light, water, pollutants

What are biotic factors?

Competition, predation

What is the importance of interdependence in a community?

Different species are dependent on each other for resources to survive.

How can CO2 be released into the environment?

Respiration of animals, respiration of plants, respiration of bacteria, burning of fossil fuels.

How is CO2 absorbed from the atmosphere?

Photosynthesis of plants/producers

What are two methods that allow water to be potable?

Desalination, distillation

Which bacteria make nitrates available for plants?

Nitrogen fixing bacteria

What do farmers do to maintain nitrogen compounds in the soil?

Crop rotation

What is the effect of adrenalin on the body?

Increased heart rate, increased blood pressure, increased blood flow to muscles, increased blood glucose levels.

Which 3 hormones control metabolic rate?

Thyroxine, TSH, TRH.

Which hormone does high levels of oestrogen stimulate the release of?

LH.

Which 2 hormones are inhibited by increasing progesterone levels?

FSH and LH.

Which gland releases FSH and LH?

Pituitary gland.

Which hormones can be used in ART and Clomifene therapy?

LH and FSH.

What is the role of glucagon in blood glucose control?

Released by pancreas, causes liver to convert glycogen into glucose, increases blood glucose.

What are adaptations of conifer trees?

Needle shape leaves (pines) to reduce surface area, thick waxy cuticle, stomata in sunken pits.

Which plant hormone causes phototropism?

Auxin

What hormone helps seeds germinate?

Gibberellins

What hormone helps fruit ripen?

Ethene gas

What is the importance of thermoregulation?

Maintain optimum temperature for enzymes.

What is the importance of osmoregulation?

Control of water and mineral salts in the body.

Which gland controls thermoregulation?

Hypothalamus

Where are temperature receptors found in the skin?

Dermis

What is vasoconstriction?

Narrowing of blood vessels when the body is cold.

What is vasodilation?

Widening of small arteries when the body is warm.

What happens to blood flow during vasoconstriction?

Reduced blood flow in capillaries near the surface of the skin.

What happens to blood flow during vasodilation?

Increased blood flow through skin capillaries.

Where is urea produced?

Liver, during the breakdown of excess amino acids.

Which vessels carry blood from the body to the kidneys?

Renal arteries

Which vessels carry blood from the kidneys to the body?

Renal veins

What is the function of the ureters?

Carry urine from the kidneys to the bladder.

What are two methods of treatment for kidney failure?

Organ donation (risk of rejection), Dialysis (needed every few days).

Where does filtration occur in the kidney?

Glomerulus and Bowman's capsule.

Where does selective reabsorption of glucose and mineral ions occur in the kidneys?

First convoluted tubule.

Where and how is water reabsorbed in the kidney?

Loop of Henle and collecting duct through osmosis.

What happens to the concentration of ADH when there is too little water in the blood?

ADH increases.

What is the equation for Fick's law?

Rate of diffusion ∝ surface area x concentration / thickness of membrane.

How does energy loss affect food chains?

The length of the chain is limited.

How can energy be lost from each trophic level in a food chain?

Metabolic processes, respiration, waste (faeces/urine).

Name two indicator species of polluted water.

Blood worm, sludgeworm.

Name two indicator species of clean water.

Freshwater shrimps, stonefly larvae.