Chapter 7
Which of the folowing statements most accurately describes the relationship between the structure and the function of cell membranes?
Cell membranes are made up of lipid bilayers that provide flexibility and form a strong barrier between a cell and its surroundings.
You will NOT find a cell wall in which of these kinds of organisms?
animals
During diffusion, when the concentration of molecules on both sides of a membrane is the same, the molecules will
continue to move across the membrane in both directions.
The cell membrane contains channels and pumps that help move materials form one side to the other. What are these channels and pumps made of?
proteins
Which of the following is a function of the cell membrane?
regulates the movement of materials into and out of the cell
Which structure makes proteins using coded instructions that come from the nucleus?
ribosome
Which of the following is a function of the nucleus?
stores DNA
Plasma membranes are selectively permeable.This means that
the plasma membrane allows some substances to enter or leave a cell more easily than others.
An animall cell that is surrounded by fresh water will burst because the osmotic pressure causes
water move into the cell
Which term describes the relativley constant internal physial conditions of an organism?
homeostatsis
The diffusion of waste across a selectively permeable membrane is called
osmosis
Diffusion does not require the cell to expend ATP. therefore, diffusion is considered a type of
passive transport
Looking at a cell under a microscope, you note that it is a prokaryote. How do do you know?
The cell lacks a nucleus.
Which of the following statements about the nucleus is NOT true?
The nulcleus is the site of protein assembly.
Which of the following is NOT a principle of the cell theory?
Very few cells are able to reproduce.
Which means of particle transport requires input of energy from the cell?
active transport
Which of the following organsisms are prokaryotes?
bacteria
Which of the following activites is NOT a way that unicellular organisms maintain homeostatsis?
cell specialization
Which organelle would you expect to find in plant cells but not animal cells?
cholorplasts
The fluid mosaic model describes the plasma membrane as consisting of
diverse proteins embedded with cholestrol sandwiched between them.
Which organelle breaks down organelles that are no longer useful?
lysosomes
Which organelle converts the chemical energy stored in food into compounds that are more convenient for the cell to use (cellular respiration)?
mitochondria
