biology year 10

What is sexual reproduction in plants?

Sexual reproduction involves the fusion of two gametes (sperm and egg) to create genetically different offspring, requiring two parent cells.

What is asexual reproduction in plants?

Asexual reproduction does not involve the fusion of gametes; it involves one parent cell only and produces genetically identical offspring (clones).

What is fertilisation in plants?

Fertilisation is the process in which a haploid male gamete (sperm) and a haploid female gamete (egg) fuse to form a diploid zygote.

What is the role of the zygote?

The zygote is a fertilised egg cell that divides by mitosis to form an embryo.

What are insect-pollinated flowers designed to attract?

Insect-pollinated flowers are often brightly coloured and have nectaries which produce sugary nectar to attract insects.

What adaptations do insect-pollinated flowers have?

Insect-pollinated flowers typically have large, brightly coloured petals, small anthers located inside the flower, and sticky large pollen grains.

What adaptations do wind-pollinated flowers have?

Wind-pollinated flowers generally have dull, small petals, long filaments to hang the anthers outside the flower, and large feathery stigmas.

What happens after pollination?

After pollination, the pollen grain germinates, grows a pollen tube down the style to the ovary, and fertilises the ovule.

What happens to the ovule after fertilisation?

The ovule develops into a seed after fertilisation.

Why is seed dispersal important?

Seed dispersal prevents competition between the offspring and the parent plant for resources such as light, water, and space.

What conditions are required for seed germination?

Seeds require water, oxygen, and optimum temperature for germination; light is not needed.

How do germinating seeds use food reserves?

Germinating seeds utilize food reserves, particularly starch, for respiration until they can perform photosynthesis.

What is a natural method of asexual reproduction seen in plants?

Runners are a natural method of asexual reproduction where a root produces a separate shoot that grows into a new plant.

What is an artificial method of asexual reproduction in plants?

Cuttings are an artificial method of asexual reproduction where a branch is removed, treated with rooting powder, and planted to grow a new plant.

How does environmental change affect asexual reproduction?

Asexual reproduction can be risky because if the environment changes or a new disease emerges, all genetically identical offspring may be wiped out.

What happens if a seed runs out of stored energy before producing leaves?

If a seed runs out of stored energy before producing leaves, it cannot complete respiration and will die.

What is the role of phloem in plants?

Phloem transports sucrose and amino acids between the leaves and other parts of the plant, allowing movement from source to sink.

What role does xylem play in plant transport?

Xylem transports water and mineral ions from the roots to other parts of the plant, enabling essential nutrient delivery.

How is water absorbed by root hair cells?

Water enters root hair cells through osmosis, which is the movement of water from a high water potential to a lower water potential through a partially permeable membrane.

What is transpiration?

Transpiration is the evaporation of water from the surface of a plant, primarily through the stomata.

What factors affect the rate of transpiration?

The rate of transpiration is affected by changes in humidity, wind speed, temperature, and light intensity.

What is osmosis?

Osmosis is the movement of water from a region of high water potential to a region of low water potential through a partially permeable membrane.

What is active transport?

Active transport is the movement of particles from a low concentration to a higher concentration against the concentration gradient, requiring energy (ATP) and a carrier protein.

How are root hair cells adapted for absorption?

Root hair cells are elongated, increasing surface area for absorption, and have thin cell walls for short diffusion distances. They also contain concentrated cell sap to increase the water potential gradient.

Why do plants need water?

Plants need water for photosynthesis (as a reactant), to maintain turgidity (support), as a solvent for transporting mineral ions, and for cooling through evaporation.

What mineral ions do plants need and their functions?

Nitrate ions are used to make amino acids and proteins; magnesium ions are needed to make chlorophyll; phosphate ions are necessary for DNA, ATP, and cell membranes.

How does water leave a leaf?

Water leaves a leaf through transpiration via the stomata, controlled by guard cells.

What is the transpiration pull?

The transpiration pull is the process by which water is pulled up the xylem to replace water lost through evaporation from the stomata.

How does temperature affect the rate of transpiration?

Higher temperatures increase the rate of transpiration because water molecules have more kinetic energy, leading to faster evaporation and diffusion out of the stomata.

What is the effect of high humidity on transpiration?

Higher humidity slows the rate of transpiration as it reduces the concentration gradient between the inside and outside of the leaf, resulting in less water diffusing out of the stomata.

What can potometers be used for?

Potometers measure the rate of transpiration by calculating water loss from a plant shoot over time.

What adaptations do xerophytic plants have to reduce water loss?

Xerophytic plants have adaptations such as a waxy cuticle to prevent water loss, sunken stomata to limit exposure to wind, rolled leaves to shelter from air movement, and hairs on leaves to trap moisture.

What are some control variables when investigating the rate of transpiration?

Control variables may include light intensity, temperature, humidity, and wind speed.

How do guard cells control stomata?

Guard cells control stomata by gaining water by osmosis (becoming turgid) to open the stomata and losing water (becoming flaccid) to close the stomata.

What is the function of the reservoir in a potometer?

The reservoir allows the air bubble to be reset for repeats of the transpiration rate experiment.

What are the four main components of blood?

1. Red blood cells

2. White blood cells

3. Platelets

4. Plasma

What is the function of plasma in the blood?

Plasma transports a number of different substances around the body, including carbon dioxide, digested food, urea, hormones, and heat energy.

What is the function of red blood cells?

The function of red blood cells is to transport oxygen from the alveoli (lungs) to respiring cells/tissues.

What adaptations do red blood cells have for their function?

Red blood cells have:

• A biconcave shape which increases surface area for oxygen diffusion
• Haemoglobin which binds to oxygen, enhancing oxygen transport
• No nucleus, allowing more space for haemoglobin.

What is the role of platelets?

Platelets help in blood clotting at the site of a wound, preventing further blood loss and the entry of pathogens.

What is the function of white blood cells?

White blood cells defend the body against pathogens that cause disease.

How do phagocytes kill pathogens?

Phagocytes engulf pathogens, enclosing them in a vesicle, then release digestive enzymes to kill and digest the pathogens.

What role do lymphocytes play in the immune response?

Lymphocytes produce specific antibodies that bind to antigens on pathogens, leading to their destruction. They also form memory cells for faster responses to future infections.

What are antigens?

Antigens are unique proteins found on the cell membrane of pathogens that our immune system recognizes.

What do vaccinations contain?

Vaccinations contain a dead or inactive form of the pathogen.

What functions does the heart serve?

The heart pumps blood around the body, delivering oxygen and nutrients while removing waste products.

Describe the structure and role of arteries.

Arteries carry blood away from the heart and have thick muscular and elastic walls to withstand high pressure.

How do veins differ from arteries?

Veins carry blood towards the heart, have a larger lumen, thinner walls, and contain valves to prevent backflow.

What is the function of capillaries?

Capillaries are involved in the exchange of substances between the blood and tissues, having thin walls for efficient diffusion.

What is coronary heart disease (CHD)?

CHD occurs when fatty material (plaque) builds up in the coronary arteries, restricting blood flow to the heart muscle.

What are some risk factors for developing coronary heart disease?

Risk factors include obesity, high blood pressure, high levels of cholesterol or saturated fats in the diet, smoking, lack of exercise, stress, and genetics.

How does the heart rate change during exercise?

During exercise, the heart rate increases to supply more oxygen and glucose to muscles, ensuring that they can respire efficiently to release energy.

What is the function of valves in the heart?

Valves prevent the backflow of blood, ensuring it flows in the correct direction through the heart and maintains pressure.

What supplies the heart muscle with oxygen and glucose?

The coronary arteries supply the cardiac muscle with oxygen and glucose necessary for respiration.

What is myogenic muscle?

Myogenic muscle refers to the heart muscles, which can contract without receiving signals from the nervous system.

What is the role of the septum in the heart?

The septum separates the left and right sides of the heart, preventing the mixing of oxygenated and deoxygenated blood.

Describe how arteries, veins, and capillaries differ structurally and functionally.

• Arteries: Thick muscle and elastic walls for high pressure; carry blood away from the heart.
• Veins: Thinner walls and larger lumen with valves; carry blood towards the heart.
• Capillaries: One cell thick for efficient diffusion; connect arteries and veins for exchange of substances.

Why does the left ventricle have a thicker wall than the right ventricle?

The left ventricle has a thicker wall to generate the higher pressure needed to pump oxygenated blood to the entire body.

What happens when the coronary arteries become blocked?

When the coronary arteries are blocked, blood flow to the heart muscle is restricted, which can lead to a heart attack (myocardial infarction).

What is the primary purpose of blood clotting?

To prevent blood loss and stop pathogens from entering the bloodstream when a blood vessel is damaged.

Explain why cholesterol levels can affect heart health.

High cholesterol can lead to plaque formation in arteries, which narrows them and increases the risk of coronary heart disease.

How do memory cells function in the immune response?

Memory cells remain in the body after infection, enabling a faster and larger antibody response if the same pathogen infects the body again.

What is the primary role of antibodies?

What is photosynthesis?

Photosynthesis is an endothermic reaction where light energy is converted into chemical energy in the form of glucose, allowing plants to produce their own food (autotrophs).

What is the word equation for photosynthesis?

Carbon dioxide + Water → Glucose + Oxygen (in the presence of light and chlorophyll).

What is the balanced chemical symbol equation for photosynthesis?

6CO2 + 6H2O → C6H12O6 + 6O2.

How do varying carbon dioxide concentration, light intensity, and temperature affect the rate of photosynthesis?

Increasing carbon dioxide concentration and light intensity generally increases the rate of photosynthesis, while temperature affects the rate until it reaches an optimum level, after which high temperatures can denature enzymes, decreasing the rate.

What are the adaptations of the leaf for photosynthesis?

Leaves have a large surface area, are thin to reduce diffusion distance, contain palisade mesophyll cells with chloroplasts for light absorption, and have stomata for gas exchange.

What role do stomata play in gas exchange?

Stomata allow carbon dioxide to enter for photosynthesis and oxygen and water vapor to exit the leaf. They are controlled by guard cells to regulate gas exchange and minimize water loss.

What are the essential mineral ions for plant growth?

Plants require mineral ions such as nitrate ions for amino acids (and thus proteins), magnesium ions for chlorophyll, and phosphate ions for DNA, ATP, and cell membranes.

What happens to a plant with a nitrate ion deficiency?

A plant with a nitrate ion deficiency shows stunted growth and yellowing of older leaves due to insufficient protein synthesis.

What happens to a plant with a magnesium ion deficiency?

A magnesium ion deficiency results in yellowing of leaves, as magnesium is needed to synthesize chlorophyll.

How is photosynthesis tested using a leaf?

To test for starch, a leaf is boiled in water to kill it, soaked in ethanol to remove chlorophyll, and then tested with iodine. A blue-black color indicates the presence of starch, confirming photosynthesis has occurred.

What is the compensation point in photosynthesis?

The compensation point is the light intensity at which the rate of photosynthesis equals the rate of respiration, resulting in no net exchange of gases.

What is the function of guard cells?

Guard cells regulate the opening and closing of stomata to control gas exchange and the loss of water vapor from the leaf.

What is the significance of chlorophyll in photosynthesis?

Chlorophyll is the green pigment in chloroplasts that absorbs light energy needed for photosynthesis, specifically absorbing red and blue light while reflecting green light.

How does temperature affect the rate of photosynthesis?

As temperature increases, the rate of photosynthesis increases because enzymes work faster; however, too high temperatures can denature enzymes, leading to a decrease in the rate of photosynthesis.

What hypothesis might a student propose regarding light intensity and rate of photosynthesis?

As light intensity increases, the rate