End of chapter 1 questions Flashcards
Which of the following comparisons of animal and plant cells is NOT true?
A: animal cells do not have chloroplasts but plant cells do.
B: animal cells have mitochondria but plant cells don’t.
C: animal cells’ vacuoles are temporary but plant cells’ vacuoles are permanent.
D: animal cells don’t have cellulose cell walls but plant cells do.
B: animal cells have mitochondria but plant cells don’t.
Which of the following descriptions ARE correct?
A: the cell wall is freely permeable and the cell membrane is partially permeable.
B: the cell wall is partially permeable and the cell membrane is freely permeable.
C: both the cell wall and the cell membrane are freely permeable.
D: both the cell wall and the cell membrane are partially permeable.
A: the cell wall is freely permeable and the cell membrane is partially permeable.
What are the products of anaerobic respiration in yeast?
A: ethanol and carbon dioxide
B: lactate and carbon dioxide
C: carbon dioxide and water
D: ethanol and water
A: ethanol and carbon dioxide
Which of the following is the best definition of “differentiation”?
A: the organization of the body into cells, tissues, and organs.
B: a type of cell division resulting in the growth of an embryo.
C: the adaptation of a cell for its function.
D: the process by which the structure of a cell becomes specialised for its function.
D: the process by which the structure of a cell becomes specialised for its function.
write down three diferences between a ‘typical’ plant cell and a ‘typical’ animal cell.
An animal cell lacks a cell wall, a large permanent vacuole and chloroplasts.
explain why the activity of an enzyme with an optimum temperature of 75° C is greater at 60° C than at 30° C.
At 60° C the molecules of the enzyme and substrate have more kinetic energy and move around more quickly. there are more frequent collisions between enzyme and substrate molecules, so more reactions are likely to take place.
the optimum temperature of enzymes in the human body is about 37° C. explain why this enzyme (which comes from a microorganism that lives in hot mineral springs near a volcano) is different
the microorganism that the enzyme comes from lives at high temperatures, so it needs ‘heat resistant’ enzymes with a high optimum temperature.
what happens to the enzyme (with an optimum temperature of 75° C) at 90° C?
It is denatured.
explain the differences between diffusion and active transport.
Diffusion is the net movement of particles (molecules or ions) from a high to low concentration. it does not need energy from respiration. Active transport uses energy from respiration to transport particles against a concentration gradient.
the nerve cell called a motor neurone and a palisade cell of a leaf are both very specialised cells. explain very briefly how each is adapted to its function.
the function of the motor neurone is to send nerve impulses to muscles and glands. it has a long axon, which conducts these impulses. it has a cell body with many extensions called dendrons and dendrites, which link with other neurones at synapses. At the other endof the neurone, the axon branches and forms connections with muscle fibres called neuromuscular junctions.
the palisade cell’s function is photosynthesis. palusade cells are near the top surface of the leaf, where they are close to the sunlight. they have thin cell wals, so the light can easily reach the many chloroplasts that the cell contains.
what is the function of the mitochondria in a tubule cell?
they carry out most of the rections of respiration in the cell, providing it with energy.
the tubule cell contains a large number of mitochondria. they are needed for the cell to transport glucose across the cell mebrane into the blood. suggest the methood that the cell uses to do this and explain your answer.
Active transport. this uses the energy from the mitochondria.
the mitochondria are not needed to transport the glucose into the cell from the tubule. name the process by which the ions move across the membrane and explain your answer.
Diffusion. the removal of glucose from the cell into the blood lowers the concentration inside the cell, so that the concentration inside the tubule is higher than inside the cell. therefore glucose can diffuse down a concentration gradient.
the surface membrane of the tubule cell is greatly folded where it meets the tubule. suggest how this adaptation helps the cell to carry out its function.
Increases the surface area for greater absorption.
