Exam 2 (1-49)

What is a cell?

• A tiny organ inside the body

• The basic unit of life; all organisms are made of one or more cells

• A protein molecule

• A molecule that stores energy

What is the cell theory?

• Cells only exist in plants

• Cells can be created spontaneously

• All living things are made of cells; cells are basic units of structure and function; all cells come from pre-existing cells

• Cells do not divide

What are the functions of the plasma membrane?

• Produces energy for the cell

• Controls what enters/exits the cell; provides protection and support; maintains homeostasis

• Stores genetic information

• Synthesizes proteins

What are the 2 primary components of the plasma membrane?

• DNA and RNA

• Phospholipids and proteins

• Carbohydrates and lipids

• Water and ions

What does “fluid mosaic” mean in reference to the plasma membrane?

• The membrane is rigid and uniform

• The membrane is a solid sheet of phospholipids

• The membrane is flexible (fluid) with varied proteins embedded (mosaic)

• The membrane is only made of proteins

Are the two sides of the membrane symmetrical or asymmetrical?

• Symmetrical

• Asymmetrical

• Both sides are identical

• None of the above

What are the 3 lipid components of the plasma membrane and their functions?

• Phospholipids (barrier), cholesterol (fluidity), glycolipids (communication)

• Triglycerides, steroids, waxes

• Proteins, nucleic acids, carbohydrates

• Saturated fats, unsaturated fats, trans fats

Which lipid makes up the majority of the membrane?

• Cholesterol

• Glycolipids

• Phospholipids

• Triglycerides

Describe a phospholipid. How are they oriented in the plasma membrane and why?

• Heads hydrophilic, tails hydrophobic; form a bilayer with tails inward to avoid water

• Heads hydrophobic, tails hydrophilic; form a single layer

• Heads and tails both hydrophilic; randomly oriented

• Heads and tails both hydrophobic; form clusters

Name 4 functions of proteins in the plasma membrane.

• Transport, communication, cell recognition, enzymatic activity

• Energy storage, insulation, cushioning, buoyancy

• Genetic information, replication, mutation, transcription

• Photosynthesis, respiration, fermentation, osmosis