Biology Practice (Interactive)

Which statement correctly describes the fluid mosaic model of cell membranes?

Sodium-potassium pumps actively transport sodium and potassium ions across the cell membrane. What is the correct ratio and direction of ion movement per cycle of the pump?

A red blood cell is placed in a solution and observed to shrink. Which statement correctly describes the solution and the net movement of water?

During aerobic respiration, in which stage of cellular respiration is the majority of ATP produced, and what is the role of the electron transport chain in this process?

In the light-dependent reactions of photosynthesis, what is the primary role of photosystem II and what product is released as a by-product?

ATP is described as the universal energy currency of cells. Which structural feature of ATP makes it particularly suitable for this role?

Which type of stem cell has the greatest differentiation potential, and where are these cells typically found in the human body?

During cell differentiation, what is the primary mechanism that causes different cell types to express different proteins despite containing the same genetic information?

A mutation changes a DNA triplet code from CAG to TAG in a gene. What type of mutation is this, and what is its most likely effect on the resulting protein?

During DNA replication, which enzyme is responsible for joining Okazaki fragments on the lagging strand, and in what direction is the lagging strand synthesised relative to the replication fork?