Exam style questions - Cells

Epithelial cells in the mammalian ileum absorb nutrients from a mammals food, explain two ways in which the cell surface membranes of these cells are adapted to their function?

A high proportion of carrier or channel proteins in order to carry nutrients via facilitated diffusion or active transport. A large surface area to maximise the rate of absorption of nutrients

Suggest why abnormal mitochondria might be problematic in heart tissue?

Abnormal mitochondria might not produce as much ATP as normal , the heart tissue may not get sufficient energy to work properly for muscle contraction.

After separating organelles from a plant the solution containing organelles is kept in a ice bath , explain why?

At lower temperatures the activity of enzymes that break down organelles is reduced

Give similarities between a sperm cell and a bacterium?

Both have a flagellum and cell membranes

A hair follicle is a sac at the root of a hair. Cells in the hair follicle divide frequently causing hair growth, suggest why non cancerous cells in the hair follicle are more affected by the chemotherapy than other non cancerous cells?

Chemotherapy aims to reduce the rate of cell division in dividing cells and other non cancerous body cells do not divide as rapidly as hair follicle cells.

Describe how to observe the cells in a prepared slide using a light microscope?

Clip the slide onto the stage , select the lowest powered objective lens, look down the eyepiece and use the coarse adjustment knob to move the stage down until the image is in focus, adjust the focus with the fine adjustment knob until you see a clear image.

Chemotherapy can prevent the production of enzymes needed for DNA synthesis . Explain why this prevents cancerous cells from dividing?

DNA synthesis is needed to double the genetic content of the cell before it divides

Give ways in which you can distinguish between a prokaryotic cell and a eukaryotic cell in an electron micrograph?

No nucleus present in prokaryotic cell , nucleus present in eukaryotic cell , a prokaryotic cell is smaller then a eukaryotic cell , the DNA in a prokaryotic cell is circular , the DNA in eukaryotic cells is linear

During ultracentrifugation what order will the organelles separate?

Nuclei , mitochondria and chloroplasts, endoplasmic reticulum, ribosomes

Explain how co-transport is used to transport sodium ions and glucose int cells in the ileum across cell membranes?

Sodium ions are actively transported out of the ileum epithelial cells into the blood by the sodium potassium pump. This creates a concentration gradient into epithelial cells via sodium-glucose co-transporter proteins . The co-transporter proteins transport glucose into the cells along with sodium ions

Suggest why the mitochondria are located close to the sperm cells flagellum ?

The flagellum requires ATP to move which is generated by mitochondria

DNA is related to the function of a sperm cell and a Mitotic body cell. a mitotic body cell has many ribosomes , but a sperm cell does not . Explain why?

The function of the sperm is to deliver genetic material to the egg , not to make proteins for cell growth and repair , having lots of organelles may reduce motility. A mitotic body cell is undergoing mitosis/division so it requires ribosomes for cell growth prior to division.

Describe the main function of mitochondria ?

The production of ATP

a 1cm length cut from onion root tip , it was incubated in dilute hydrochloric acid for 5 mins at 60 degrees , then rinsed well in cold water and left to dry . How could the student prepare a microscope slide to view the cells in this root tip ?

The student could place the root tip on a microscope slide and cut a small section from the very tip of it . Then used a mounted needle to break the tip open and spread the cells out thinly. Add a few drops of stain and left for a few minutes . Then place a cover slip over the cells and push down firmly

A scientist was separating organelles from a sample of plant cells , describe how the scientist could separate the organelles from other plant cell components?

They could add a buffer solution to the sample , grind the cells in a blender then filter the solution to remove the cell and tissue debris

A scientist wanted to observe the mitochondria in a sample of sperm , which type of microscope should the scientists use to study the internal structures of the mitochondria ?

Transmission/Scanning electron microscope as these have a higher resolution than light microscopes which would be needed to study the internal detail of mitochondria

Explain the replication of a virus ?

Virus replicate by injecting their DNA or RNA into a host cell causing it to burst and release infective bodies that infect other cells