QCM : Fundamentals of Living Organisms and Processes — 24 questions

Explication

A living organism is defined by carrying out life processes such as growth, reproduction, and response to stimuli. The other options describe either non-living objects or broader ecological groupings.

Explication

Classification groups organisms based on shared characteristics to organise variety and show relationships. It is broader than simply naming organisms or splitting them into two groups.

Explication

Cells form tissues, tissues form organs, and organs form organ systems. This increasing level of organisation is the standard hierarchy.

Explication

An organelle is a specialised structure within a cell with a particular job. The other options describe a tissue, an organ, and an organ system.

Explication

Plant cells have a cell wall, while animal cells do not. Mitochondria, cytoplasm, and cell membranes are found in both.

Explication

Mitochondria are the organelles where respiration releases energy, especially in aerobic conditions. Genetic information is stored in the nucleus, not in mitochondria.

Explication

Diffusion is the net movement of particles down a concentration gradient, from higher to lower concentration. Osmosis and active transport are different processes.

Explication

Active transport uses energy to move substances against a concentration gradient. The other options describe osmosis or diffusion.

Explication

Aerobic respiration uses oxygen to release energy from food molecules. Carbon dioxide and water are products of the process, not the reactant used.

Explication

Aerobic respiration uses oxygen, keeping its concentration low inside the cell and maintaining a diffusion gradient into the cell. The membrane does allow oxygen to diffuse through.

Explication

A hypotonic solution has a higher water potential than the potato cells, so water moves in by osmosis. This increases both mass and length.

Explication

Repeating the experiment and calculating a mean improves reliability. Excessive blotting can change the measured mass and increase error.

Explication

Fertilisation is the joining of male and female gametes to form a zygote. Growth into an embryo happens after fertilisation.

Explication

In humans, the zygote divides and develops into an embryo, which then develops into a baby. Seeds and fruits are plant reproductive structures.

Explication

A gene is a section of DNA that codes for a specific characteristic. Chromosomes carry many genes, but a gene is not a chromosome itself.

Explication

Different alleles of the same gene can lead to different traits or phenotypes. This variation comes from the different versions of genes inherited from parents.

Explication

A steeper concentration gradient increases the rate of diffusion because there is a larger difference between the two areas. Active transport and osmosis are different processes.

Explication

In a hypertonic solution, water moves out of the cell by osmosis, so the cell shrinks or crenates. Swelling happens in a hypotonic solution.

Explication

Double circulation means blood passes through the heart twice in one full circuit of the body. This separates oxygenated and deoxygenated blood more effectively.

Explication

Alveoli are the tiny air sacs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out. They do not pump blood or store oxygen.

Explication

Pasteurisation kills unwanted bacteria that could contaminate the milk or compete with Lactobacillus. After pasteurising, the milk is cooled before the starter bacteria are added.

Explication

Lactobacillus ferments lactose to form lactic acid, which lowers pH and thickens the milk. Ethanol is associated with yeast fermentation, not yoghurt production.

Explication

Selective breeding involves choosing parents with desired traits so the offspring are more likely to show those traits. Genetic modification and cloning are different processes.

Explication

Cloning produces genetically identical copies of an organism or cells. Selective breeding mixes traits through reproduction rather than making identical copies.