Key Concepts in Biology: Immune System and Cell Functions

What is the role of white blood cells in the immune system?

White blood cells detect pathogens and produce antibodies.

How do vaccines trigger an immune response?

Vaccines introduce a dead pathogen, which triggers the immune response, killing the pathogen and creating memory cells for a faster response upon future infections.

What happens during Stage 1 of the cell cycle?

DNA replicates to form 2 copies of each chromosome, and the number of subcellular structures such as mitochondria and ribosomes increases.

What occurs in Stage 2 of the cell cycle?

One set of chromosomes is pulled to each side of the cell, and the nucleus divides to form 2 nuclei.

Describe Stage 3 of the cell cycle.

The cytoplasm and cell membrane divide, forming 2 identical daughter cells.

What effect does a partly blocked coronary artery have on the body?

Blood flow to the heart muscle is reduced, leading to less oxygen and glucose for heart cells, resulting in less aerobic respiration, more anaerobic respiration, and increased lactic acid, causing muscle pain and fatigue.

How does tobacco mosaic virus affect plant growth?

TMV causes leaf discoloration, leading to a lack of chlorophyll, which decreases photosynthesis and results in less glucose and essential growth materials.

Name three ways white blood cells protect against pathogens.

1. Lymphocytes produce antibodies that bind to antigens. 2. Phagocytes engulf and destroy pathogens. 3. They produce antitoxins.

How does the human body prevent pathogens from entering?

The body uses non-specific defense systems like the skin, nose, trachea, bronchus, and stomach.

What are monoclonal antibodies?

Identical antibodies produced from a single clone of cells that bind to one specific antigen.

How are monoclonal antibodies produced?

A mouse is injected with a specific antigen, its lymphocytes produce antibodies, which are combined with tumor cells to form hybridoma cells that divide rapidly to produce antibodies.

What adaptations does the gas exchange system have for efficient gas exchange?

It has a large surface area, short diffusion path, efficient blood supply, and good ventilation.

What is the procedure for preparing a slide for microscopy?

Use a thin section of the sample, place it on a slide with stain, start with the lowest power objective lens, and adjust focus. Multiply eyepiece and objective lens magnifications for total magnification.

What color change indicates the presence of protein in a Biuret test?

The solution turns from blue to purple.

What color change indicates the presence of starch in an iodine test?

The solution turns from orange to blue-black.

What color change indicates the presence of sugar in a Benedict's test?

The solution turns from blue to brick red when heated.

What is the difference between aerobic and anaerobic respiration?

Aerobic respiration requires glucose and oxygen, completely breaks down glucose, and produces carbon dioxide and water, while anaerobic respiration only requires glucose, does not completely break down glucose, and produces carbon dioxide and ethanol (in plants and yeast) or lactic acid (in animals).

What is the role of bile in digestion?

Bile, made in the liver and stored in the gallbladder, emulsifies fats in the small intestine to increase surface area for lipase action.

What is amylase?

An enzyme made in the salivary glands that breaks down starch into glucose.

What are villi?

Cells in the small intestine that absorb nutrients into the bloodstream, shaped to maximize surface area.

What are enzymes?

Biological catalysts that break down large molecules into smaller ones, speeding up reactions without being used up.

How are enzymes specific?

Enzymes only break down certain molecules due to the lock and key mechanism, where only substrates with the right shape fit the active site.

What happens to enzyme activity when temperature increases?

Enzyme activity increases due to higher kinetic energy until it denatures, changing the active site's shape.

Describe the structure and function of alveoli.

Alveoli are air sacs in the lungs where gas exchange occurs, with a large surface area to maximize diffusion of oxygen in and CO2 out.

What is the function of red blood cells?

Red blood cells transport oxygen around the body via the bloodstream, with a biconcave shape that maximizes surface area for oxygen binding.

What is the pathway of blood through the heart?

Blood enters through the vena cava into the right atrium, then the right ventricle, exits through the pulmonary artery to the lungs, returns via the pulmonary vein into the left atrium, then the left ventricle, and leaves through the aorta to the body.

How does the left side of the heart differ from the right?

The left side has thicker walls and pumps blood at higher pressure to the whole body, while the right side has thinner walls and pumps blood only to the lungs.

What are the differences between arteries, veins, and capillaries?

Arteries carry oxygenated blood away from the heart with thick walls and high pressure; veins carry deoxygenated blood to the heart with thin walls and valves; capillaries are one cell thick for fast diffusion.

What are risk factors for non-communicable diseases?

Diet, obesity, lack of exercise, alcohol consumption, and smoking.

What is cancer and the difference between benign and malignant tumors?

Cancer is the uncontrollable division of cells forming tumors. Benign tumors do not spread, while malignant tumors do.

What is the function of xylem and phloem?

Xylem carries water unidirectionally up the plant, while phloem carries nutrients bidirectionally using active transport.

What factors increase the rate of transpiration?

Higher temperature, increased air flow, and larger surface area of leaves.

What is the function of meristem?

Meristem is made of stem cells that can differentiate into other plant cells.

What is the structure and function of the waxy cuticle, palisade mesophyll, spongy mesophyll, and guard cells?

The waxy cuticle is a waterproof layer that prevents water evaporation; palisade mesophyll contains chloroplasts for photosynthesis; spongy mesophyll facilitates gas exchange; guard cells control the size of stomata.

What do plants use glucose for?

Plants use glucose for respiration, making amino acids, starch, fat, and cellulose.

What factors can increase the rate of photosynthesis?

Higher temperature, increased light intensity, and increased CO2 concentration.

What is the difference between blind and double-blind trials?

In blind trials, subjects do not know their group assignment; in double-blind trials, neither subjects nor doctors know the group assignments to eliminate bias.