Acids, Bases and Salts
What do you mean by pH?
Power of Hydrogen or the measurement of the acidity and alkalinity of a substance.
Is burning wood an example of an exothermic or endothermic reaction?
Exothermic
Where does most digestion take place in the human body?
Small Intestine
What is the main function of red blood cells?
To transport oxygen.
What is a pathogen?
Disease causing microorganism.
Which ion is responsible for the basic nature of a substance?
OH⁻ (hydroxide ion)
What is the energy change that occurs in an exothermic reaction?
Energy is released to the surroundings
Which enzyme breaks down starch into maltose?
Maltose
Which blood vessels carry blood away from the heart to the bodily organs?
Aorta/Artery
Differentiate phagocytes from lymphocytes.
Both are types of White blood cells and fight pathogen. They vary according to the mechanism of how they destroy the pathogen. Phagocytes do phagocytosis where it engulfs itself to the pathogen itself, digesting and destroying it in the process, while Lymphocytes creates/produces antibodies that inhibits the growth and development of the pathogen.
Name the type of reaction between an acid and a base that produces salt and water.
Neutralisation
What do you call the minimum amount of energy needed for a chemical reaction to occur?
Activation Energy
What is the role of bile in digestion?
It emulsifies fats, breaking them into smaller droplets.
What component in the blood helps with clotting?
Platelets
What are vaccines?
A weakened or inactive form of a pathogen used to stimulate immunity.
What salt is formed when hydrochloric acid reacts with sodium hydroxide?
Sodium chloride (NaCl)
In a chemical reaction, the energy of the products is higher than that of the reactants. What type of reaction is this?
Endothermic
What is peristalsis and what role does it play in digestion?
Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract.
Name the valve that prevents backflow of blood between the left atrium and left ventricle.
Bicuspid (mitral) valve
What is the difference between an antigen and an antibody?
An antigen is a substance that triggers an immune response, while an antibody is a protein produced by the immune system to recognize and neutralize the antigen.
A student adds a few drops of phenolphthalein to a solution and it turns pink. What can you conclude about the solution, and why?
It is basic, because phenolphthalein turns pink in bases.
A student records temperature decrease when mixing two substances. Explain what this indicates about the reaction and the energy transfer involved.
It is an endothermic reaction; energy is absorbed from the surroundings, lowering the temperature.
Explain how the structure of villi helps in the absorption of digested food in the small intestine.
Villi increase surface area and contain capillaries for efficient absorption of nutrients.
Explain the path of blood through the heart starting from the right atrium.
Right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta → body.
Explain how the body uses memory cells to respond faster to a second infection by the same pathogen.
Memory cells recognize the pathogen and trigger a quicker, stronger immune response, preventing illness.