A-Level Biology Quiz: Open Evening

Which of the following is NOT a feature of a prokaryotic cell?

• Circular DNA

• Ribosomes

• Mitochondria

• Cell membrane

Answer explanation

Mitochondria are membrane-bound organelles found in eukaryotic cells, not prokaryotic cells. Prokaryotic cells have circular DNA, ribosomes, and a cell membrane, but lack mitochondria.

Enzymes are biological catalysts. What does this mean?

• They speed up reactions and are consumed in the process.

• They speed up reactions without being used up.

• They slow down reactions but ensure they occur correctly.

• They stop reactions from happening.

Answer explanation

Enzymes are biological catalysts that speed up reactions without being consumed in the process. This means they can facilitate multiple reactions without being used up, making them essential for various biological functions.

Which of the following is a polymer?

• Glucose

• Starch

• Amino acid

• Fatty acid

Answer explanation

Starch is a polymer made up of many glucose units linked together, making it a complex carbohydrate. In contrast, glucose, amino acids, and fatty acids are monomers or building blocks, not polymers.

In which organelle does photosynthesis occur?

• Nucleus

• Ribosome

• Chloroplast

• Golgi apparatus

Answer explanation

Photosynthesis occurs in the chloroplast, an organelle found in plant cells. It contains chlorophyll, which captures sunlight to convert carbon dioxide and water into glucose and oxygen.

Which term describes the movement of water across a partially permeable membrane?

• Diffusion

• Osmosis

• Active transport

• Facilitated diffusion

Answer explanation

Osmosis specifically refers to the movement of water across a partially permeable membrane, driven by differences in solute concentration. This distinguishes it from diffusion, which involves the movement of solutes.

What is the main function of red blood cells?

• To fight infection

• To carry oxygen

• To transport hormones

• To produce antibodies

Answer explanation

The main function of red blood cells is to carry oxygen from the lungs to the body's tissues. They contain hemoglobin, which binds to oxygen, making this their primary role, unlike the other options which pertain to different functions.

Which type of bond holds the two strands of DNA together?

• Ionic bonds

• Covalent bonds

• Hydrogen bonds

• Disulfide bonds

Answer explanation

Hydrogen bonds hold the two strands of DNA together by forming between the nitrogenous bases. These weak bonds allow the strands to separate during replication while maintaining the overall structure.

What is the role of the ribosome?

• To store genetic information

• To produce energy for the cell

• To synthesise proteins

• To transport substances across the cell

Answer explanation

The ribosome's primary role is to synthesise proteins by translating messenger RNA (mRNA) into amino acid sequences, making it essential for cell function and growth.

Which of these is an abiotic factor in an ecosystem?

• Plants

• Animals

• Soil pH

• Microorganisms

Answer explanation

Soil pH is an abiotic factor, as it refers to the chemical and physical properties of the environment. In contrast, plants, animals, and microorganisms are all biotic factors, as they are living organisms.

Which of the following best describes the process of natural selection?

• Organisms choose their adaptations to suit the environment.

• Only the largest and strongest survive to reproduce.

• Random mutations create variation, and individuals best suited to their environment survive to reproduce.

• Evolution occurs when all individuals in a population develop the same traits.

Answer explanation

Natural selection is driven by random mutations that create variation. Those individuals best suited to their environment are more likely to survive and reproduce, leading to the evolution of species.