Chapter 4 – Cell Components, Membranes, and Transport

A set of flashcards covering cytoplasm, membrane components, transport mechanisms, cytoskeletal elements, differences between prokaryotic and eukaryotic cells, and related cellular processes from Chapter 4.

What is the name for everything inside a cell except the nucleus?

Cytoplasm

Which molecules primarily make up the cell membrane?

Phospholipids

Are the phospholipids in cellular membranes molecularly identical or diverse?

They are molecularly diverse.

What are integral membrane proteins?

Proteins that are embedded partially or fully in the phospholipid bilayer.

Why do membrane proteins from fused mouse–human cells become evenly distributed across the hybrid membrane?

Because many membrane proteins can move laterally within the lipid bilayer.

During facilitated diffusion, why does the transport rate level off as the concentration difference becomes very large?

Carrier proteins become saturated.

What is the key difference between osmosis and diffusion?

Osmosis specifically refers to the movement of water, whereas diffusion can involve any substance.

Name three factors that affect the rate of diffusion across a membrane.

Concentration gradient, temperature, and size of the diffusing molecules.

Is facilitated diffusion considered passive or active transport?

Passive transport.

What term describes the nonspecific uptake of extracellular fluid and dissolved solutes by a cell?

Pinocytosis

What happens to material enclosed in a phagosome after phagocytosis?

The phagosome fuses with a lysosome whose enzymes digest the material.

Which two cellular processes both require membrane-enclosed vesicles?

Endocytosis and exocytosis.

Which cytoskeletal structures are directly involved in the movement of organelles within a cell?

Microtubules

Why are most cells small?

A larger surface area-to-volume ratio increases the efficiency of cellular processes.

As a cell grows larger, how do its metabolic needs change?

Its need for resources increases.

What protein subunits make up microfilaments?

Actin monomers.

Where are plasma-membrane proteins synthesized and where are carbohydrates added to them?

Proteins are synthesized in the rough endoplasmic reticulum, and carbohydrates are added in the Golgi apparatus.

What is a major structural difference between prokaryotic and eukaryotic cells?

Prokaryotic cells do not have membrane-enclosed compartments (organelles).

In prokaryotic cells, where is the DNA located?

In the nucleoid region.

Ribosomes are composed of which two types of molecules?

RNA and proteins.