Biology

What defines a eukaryote?

An organism whose cells contain a nucleus enclosed by a membrane.

What are the four main kingdoms of eukaryotes?

Plants, Animals, Fungi, and Protoctists.

What are three defining features of plant cells?

Cellulose cell walls, chloroplasts for photosynthesis, and carbohydrate storage as starch or sucrose.

How do animal cells store carbohydrates?

As glycogen.

What is the composition of a fungal cell wall?

Chitin.

What is the structural organization of a fungus?

A network of thread-like hyphae forming a mycelium.

What is saprotrophic nutrition?

The process of secreting enzymes externally to digest food and then absorbing the nutrients.

Provide a multicellular and a single-celled example of fungi.

Mucor (multicellular) and yeast (single-celled).

What are protoctists?

Mostly single-celled, microscopic eukaryotes that can resemble either animals or plants.

Which protoctist is responsible for malaria?

Plasmodium.

What is the primary difference between prokaryotes and eukaryotes regarding DNA?

Prokaryotes lack a true nucleus; their DNA is circular and free in the cytoplasm.

What are plasmids in prokaryotic cells?

Small rings of DNA.

What structures are found in bacterial cells?

Cell wall, cell membrane, cytoplasm, ribosomes, circular DNA, and plasmids.

What is an example of a rod-shaped bacterium and its application?

Lactobacillus bulgaricus, used to make yogurt.

What is an example of a spherical bacterium and the disease it causes?

Pneumococcus, which causes pneumonia.

What is the correct order of biological organization from smallest to largest?

Organelles → Cells → Tissues → Organs → Organ Systems

What is the primary function of the nucleus?

Contains DNA and controls cell activities

What is the function of the cell membrane?

Controls what enters and leaves the cell

What process occurs in the mitochondria?

Aerobic respiration, which produces ATP

What is the function of chloroplasts?

Site of photosynthesis

What is the role of ribosomes?

Protein synthesis

What are the two functions of the vacuole in plant cells?

Stores substances and maintains turgor pressure

Which three structures are found in plant cells but not in animal cells?

Cell wall, chloroplasts, and a large permanent vacuole

Which chemical elements make up carbohydrates?

Carbon, hydrogen, and oxygen

Which chemical elements make up proteins?

Carbon, hydrogen, oxygen, and nitrogen

What are the building blocks of proteins?

Amino acids

What are the building blocks of lipids?

Fatty acids and glycerol

What are the building blocks of carbohydrates?

Simple sugars (e.g., glucose)

What reagent is used to test for glucose and what indicates a positive result?

Benedict's solution; blue turns to orange or brick red upon heating.

What reagent is used to test for starch and what indicates a positive result?

Iodine solution; brown turns to blue-black.

What reagent is used to test for protein and what indicates a positive result?

Biuret reagent; blue turns to purple or lilac.

What is the test for fat and what indicates a positive result?

Ethanol emulsion test; a cloudy white emulsion forms.

Define diffusion.

The passive movement of particles from an area of high concentration to an area of low concentration.

Define osmosis.

The passive movement of water molecules through a partially permeable membrane from a dilute to a concentrated solution.

Define active transport.

The movement of substances against the concentration gradient, requiring ATP.

What happens to a potato chip placed in a concentrated sugar solution?

It loses mass as water moves out of the chip via osmosis.

What happens to a potato chip placed in pure water?

It gains mass as water moves into the chip via osmosis.

What are the four factors that affect the rate of diffusion?

Surface area to volume ratio, distance, temperature, and concentration gradient.

What is the word equation for photosynthesis?

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

What is the symbol equation for photosynthesis?

6CO2 + 6H2O → C6H12O6 + 6O2

What are the three limiting factors of photosynthesis?

Light intensity, CO2 concentration, and temperature.

Does diffusion require energy?

No, it is a passive process.

Does osmosis require energy?

No, it is a passive process.

What is the primary energy source required for active transport?

ATP.

Why does very high temperature reduce the rate of photosynthesis?

Enzymes become less efficient and eventually denature.

How does the shape of a leaf assist in light absorption?

Its broad, flat shape maximizes the surface area.

Why are leaves thin?

To provide a short diffusion distance for gases.

Why are chloroplasts concentrated in the palisade layer?

It is near the top surface of the leaf, providing maximum exposure to light.

What is the function of stomata in leaves?

They allow CO2 to enter and O2 to leave during photosynthesis.

Which mineral ion is required for protein synthesis and what is its deficiency symptom?

Nitrate; deficiency causes stunted growth and yellow leaves.

Which mineral ion is required for chlorophyll production and what is its deficiency symptom?

Magnesium; deficiency causes chlorosis (yellow leaves).

What is the primary function of carbohydrates in the diet?

Providing energy.

What is the primary function of proteins in the diet?

Growth and repair.

What are the primary functions of lipids in the diet?

Energy storage and insulation.

What is the biological role of vitamin D?

Calcium absorption and the maintenance of strong bones.

Why is iron necessary in the human body?

It is required for making haemoglobin in red blood cells.

What is the function of dietary fibre?

Maintaining a healthy digestive system.

What three factors influence a person's energy requirements?

Age, activity level, and pregnancy.

What is the correct sequence of organs in the alimentary canal?

Mouth → Oesophagus → Stomach → Small intestine (Duodenum → Ileum) → Large intestine (Colon → Rectum) → Anus.

What are the substrates and products of amylase digestion?

Starch is broken down into maltose.

What are the substrates and products of maltase digestion?

Maltose is broken down into glucose.

What are the substrates and products of protease digestion?

Proteins are broken down into amino acids.

What are the substrates and products of lipase digestion?

Lipids are broken down into fatty acids and glycerol.

Where is amylase produced in the body?

The mouth and the pancreas.

Where is protease produced in the body?

The stomach and the pancreas.

Where is lipase produced in the body?

The pancreas.

What is the word equation for aerobic respiration?

Glucose + Oxygen → Carbon dioxide + Water + Energy.

What is the symbol equation for aerobic respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.

In which organelle does aerobic respiration occur?

The mitochondria.

Does respiration only occur during exercise?

No, it occurs in all living cells at all times.

What is the function of the alveoli?

They are tiny air sacs where gas exchange occurs.

What is the role of the diaphragm in breathing?

It is a dome-shaped muscle below the lungs that facilitates ventilation.

What happens to the diaphragm and ribs during inhalation?

The diaphragm contracts and flattens, and the ribs move up and out.

How do lung pressure and volume change during inhalation?

Volume increases and pressure decreases, causing air to rush in.

What physical changes occur during exhalation?

Intercostal muscles relax, ribs move down and in, the diaphragm domes up, lung volume decreases, and pressure increases, forcing air out.

How does tar in cigarettes affect the lungs?

It coats the alveoli, reducing surface area for gas exchange, and introduces carcinogens.

What are the physiological effects of nicotine?

It is addictive and raises blood pressure.

How does carbon monoxide in cigarette smoke impact blood?

It binds to haemoglobin, reducing its oxygen-carrying capacity.

What is the effect of particulates in cigarette smoke on the respiratory system?

They damage cilia, leading to mucus build-up and smoker's cough.

What are four diseases linked to smoking?

Lung cancer, chronic bronchitis, emphysema, and coronary heart disease.

What does xylem transport and in what direction?

Water and mineral ions from roots to leaves in a one-way, upward direction.

What is the cellular structure of xylem?

Dead, hollow cells.

By what process does water enter root hair cells?

Osmosis.

By what process do mineral ions enter root hair cells?

Active transport.

Define transpiration.

The loss of water vapour from plant leaves through the stomata.

What is the transpiration stream?

The movement of water from roots to stem to leaves, followed by evaporation through the stomata.

How does temperature affect the rate of transpiration?

It increases the rate by promoting more evaporation.

How does humidity affect the rate of transpiration?

It decreases the rate by reducing the concentration gradient between the leaf and the air.

How does wind speed affect the rate of transpiration?

It increases the rate by removing humid air from the leaf surface, steepening the concentration gradient.

How does light intensity affect the rate of transpiration?

It increases the rate by causing the stomata to open wider.

What instrument is used to measure water uptake in a plant?

A potometer.

What are the primary characteristics of sexual reproduction?

Involves two parents, the production of gametes, genetic variation, and meiosis.

What are the primary characteristics of asexual reproduction?

Involves one parent, no gametes, results in clones, and utilizes mitosis.

Name two examples of organisms that reproduce asexually.

Bacteria and potato tubers.

Which type of cell division is responsible for producing gametes?

Meiosis.

Which type of cell division is used in asexual reproduction?

Mitosis.

What are three defining features of insect-pollinated flowers?

Large, colorful, scented petals; presence of nectar; sticky or spiky pollen.

What are three defining features of wind-pollinated flowers?

Small, dull, odorless petals; no nectar; light, smooth, abundant pollen with feathery stigmas hanging outside the flower.

What is the function of FSH in the menstrual cycle?

Stimulates follicle development and oestrogen production; produced by the pituitary gland.

What are the primary roles of oestrogen in the menstrual cycle?

Repairs the uterus lining and triggers the release of LH.