Cell Physiology Chapter 1 Quiz

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Questions and Answers

What is the structure of the plasma membrane?

Consists of two layers of phospholipids with embedded proteins and sugars

What is the function of the plasma membrane?

Control passage of substances into and out of the cell, regulating the intracellular environment

What are the components of the plasma membrane?

Phospholipids, proteins, sugars, and cholesterol

How are the phospholipid molecules arranged in the plasma membrane?

Arranged like a sandwich with the hydrophilic heads on the outer surfaces and the hydrophobic tails forming a central water-repelling layer Signup and view all the answers

What role do membrane proteins play in the plasma membrane?

Provide channels for the passage of substances and electrolytes Signup and view all the answers

What is the function of cholesterol in the plasma membrane?

Present in the membrane Signup and view all the answers

What is the function of membrane proteins with branched carbohydrate molecules attached to the outside of the cell?

They give the cell its immunological identity - 'self' markers. Signup and view all the answers

What are some functions of membrane proteins?

Act as receptors for hormones and other chemical messengers, and some are enzymes. Signup and view all the answers

What is the property of the plasma membrane that allows it to control the entry or exit of substances?

Selective permeability. Signup and view all the answers

How do lipid-soluble materials cross the membrane?

By dissolving in the lipid part of the membrane. Signup and view all the answers

What is the process used by substances that are unable to diffuse through the semipermeable membrane unaided?

Facilitated diffusion. Signup and view all the answers

What is osmosis?

Passive movement of water down its concentration gradient towards equilibrium across a semipermeable membrane. Signup and view all the answers

What is active transport?

The transport of substances up their concentration gradient using chemical energy in the form of ATP. Signup and view all the answers

What is the function of the sodium-potassium pump?

It maintains the unequal concentrations of sodium and potassium ions on either side of the plasma membrane. Signup and view all the answers

How are particles too large to cross cell membranes transferred?

By pinocytosis ('cell-drinking') or phagocytosis ('cell-eating'). Signup and view all the answers

What is the term for the process of extrusion of waste material through the plasma membrane?

Exocytosis. Signup and view all the answers

What are organelles?

Individual and highly specialised structures enclosed by their own membrane within the cytosol. Signup and view all the answers

Which cells contain several nuclei?

Skeletal muscle fibres and some other cells. Signup and view all the answers

What is the name of the fine network of threads that DNA is present as in a non-dividing cell?

Chromatin Signup and view all the answers

What is the function of the nucleus?

Directs all metabolic activities and contains genetic material in the form of DNA. Signup and view all the answers

What is the role of the nucleolus within the nucleus?

Involved in synthesis and assembly of the components of ribosomes. Signup and view all the answers

What is the main function of mitochondria?

Central to aerobic respiration and the production of ATP. Signup and view all the answers

What are ribosomes composed of?

RNA and protein Signup and view all the answers

What is the role of smooth endoplasmic reticulum?

Synthesises lipids and steroid hormones, and is associated with the detoxification of some drugs. Signup and view all the answers

What is the site of synthesis of proteins in a cell?

Rough endoplasmic reticulum and ribosomes Signup and view all the answers

Where do the proteins move from the endoplasmic reticulum to be 'packaged' into membrane-bound vesicles?

Golgi apparatus Signup and view all the answers

What is the main function of lysosomes?

Contain enzymes involved in breaking down fragments of organelles and large molecules inside the cell into smaller particles. Signup and view all the answers

What is the function of the nuclear envelope?

It contains the nucleus and has tiny pores through which some substances can pass between it and the cytoplasm. Signup and view all the answers

What is the form of energy made available in the cell by mitochondria?

ATP Signup and view all the answers

What is the main function of the Golgi apparatus?

To 'package' proteins into membrane-bound vesicles and move them to the plasma membrane for exocytosis. Signup and view all the answers

Flashcards

Plasma membrane structure

Two layers of phospholipids with embedded proteins and sugars.

Plasma membrane function

Controls what enters and leaves the cell.