Connect cellular structure and gene expression to development, then apply classification, diversity measures and conservation evidence with precise terminology and units.
The photograph shows two human cheek cells on a microscope slide. The mean diameter of human cheek cells is .
Describe a procedure for the accurate determination of the diameter of cell A .
Draw cell A and label the parts of the cell. Include a scale by your drawing.
The photograph below shows part of a transverse section of a plant stem.
Three types of cell are labelled X, Y and Z.
Identify the cell types labelled X, Y and Z. X Y Z
The photograph shows a longitudinal section of where two plant cells meet.
State which of the cells labelled X, Y or Z is shown in this longitudinal section.
Cell
Female mosquitoes feed on the blood of other animals to promote the development of their eggs. During this process, infected mosquitoes can transmit the Plasmodium parasite.
The Plasmodium parasite causes the disease malaria.
The photograph shows a female Anopheles mosquito.
The fungus Metarhizium pingshaense infects Anopheles mosquitoes.
A student drew a labelled diagram of a fungal cell that was dividing.
State the function of a nucleolus.
Give three differences in ultrastructure between this cell and a cell taken from the root of a plant.
The five stages of cancer are used to describe the size and spread of a cancer in a human body.
The mitotic index of a tissue can be used to determine the stage of cancer.
A higher mitotic index is usually linked to a later stage of cancer.
The mitotic index is calculated using the formula
Tests were performed on three patients, P, Q and R, who had cancer.
The table shows the number of cells that were counted in each stage of the cell cycle per of tissue, taken from the same organ in each patient.
State what is meant by the term tissue.
Anticancer drugs have to undergo double-blind trials before they are used to treat patients.
Describe how a placebo is used in a double-blind trial.
A plant contains several types of cells, tissues and organs.
State what is meant by the term organ.
The photograph shows part of a cell.
© Jose Calvo / Alamy Stock Photo
Which organelle is labelled X ?
chloroplast
endoplasmic reticulum
Golgi apparatus
plasmodesmata
The organelle surrounded by the membrane labelled Y contains the nucleolus. Give the name and function of the organelle that contains the nucleolus. Name Function
Which of the following are functions of the nucleolus? 1. production of ribosomes 2. synthesis of DNA 3. synthesis of RNA
1 and 2 only
1 and 3 only
2 and 3 only
1, 2 and 3
Organisms can be classified into three domains. State which of the three domains would contain an organism with the organelles X and Y .
The drawing shows tubers of a potato plant developing below the surface of the soil.
Organic molecules are transported through the potato plant to the developing tubers. These molecules can be used to form starch molecules.
Which structure in the cells of these tubers would store starch molecules?
amyloplast
chloroplast
middle lamella
vacuole
Explain how the structure of starch enables the potato tubers to have a high energy content.