Chapter 3: Cells, Part 1 Practice Flashcards

A set of practice questions and answers covering cellular structure, organelles, membrane properties, and specialized cell functions as described in Chapter 3.

What is considered the basic unit of structure and function in the body?

The cell.

In what unit are cells measured?

$$\text{micrometers}$$

What term describes cells that have developed specialized characteristics?

Differentiated.

How do the long extensions of a nerve cell relate to its function?

They enable the cell to conduct electrical impulses from one body part to another.

What are the three major parts of a composite cell?

Nucleus, Cytoplasm, and Cell membrane.

What are the functions of the cell (plasma) membrane?

It maintains cell integrity, separates intracellular fluid (cytosol) from extracellular fluid, regulates the entry and exit of substances (selectively permeable), and permits signal transduction.

Describe the structure of the phospholipid bilayer in the cell membrane.

It consists of water-soluble (hydrophilic) heads forming the surfaces and water-insoluble (hydrophobic) tails forming the interior.

What is the function of cholesterol within the cell membrane?

It stabilizes the membrane and helps keep it impermeable to water-soluble substances.

What are the primary components of the cytoplasm?

Cytosol (the fluid portion) and organelles (tiny solid structures with specific functions).

What are ribosomes composed of and what is their function?

They are composed of protein and RNA; they provide structural support and enzyme activity to link amino acids in protein synthesis.

How do the Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER) differ?

Rough ER contains ribosomes and conducts protein synthesis, while Smooth ER lacks ribosomes and conducts lipid synthesis.

What is the role of the Golgi apparatus?

It consists of flattened membranous sacs that refine, package, and deliver proteins made on the RER.

Milk secretion is an example of an interaction between which organelles?

Rough and smooth ER, Golgi apparatus, and transport vesicles.

Why are mitochondria often called the 'powerhouse of the cell'?

They house chemical reactions (cellular respiration) that extract energy from nutrients to produce $\text{ATP}$.

What is the function of lysosomes?

They contain enzymes that digest proteins, carbohydrates, nucleic acids, bacteria, debris, and worn out cell parts.

What substances do the enzymes in peroxisomes digest?

Lipids, alcohol, and hydrogen peroxide.

What are microfilaments made of and what do they provide?

They are tiny rods of actin that provide cellular movement, such as muscle contraction.

What is the composition and function of microtubules?

They are larger tubes of tubulin that maintain cell shape, make up cilia and flagella, and help move organelles.

What is the role of centrioles during cell division?

They produce spindle fibers which distribute chromosomes to forming daughter cells.

How do cilia and flagella differ in a human cell?

Cilia are short, abundant extensions that beat back and forth to propel mucus or eggs; a flagellum is much longer, causes the entire cell to move, and in humans is only found as the tail of a sperm cell.

What is the nucleolus and what happens there?

It is a dense body of RNA and protein that serves as the site of ribosome production.

What is the function of chromatin?

It consists of chromosomes made of DNA wound around proteins; it stores information for protein synthesis.