Chapter 4

Question 1

What contributions did Leeuwenhoek, Hooke, Schleiden and Schwann make to our knowledge of cells?

Answer 1

Leeuwenhoek-first to view single-celled organisms; later discovered bacteria and protozoa
Hooke-coined the term cell when looking at cork tissue
Schleiden and Schwann-proposed the unified cell theory

Question 2

What is the unified cell theory, and what does it say?

Answer 2

All living things are composed of one or more cells, the cell is the basic unit of life, new cells arise from existing cells

Question 3

Name the four components common to all living cells.

Answer 3

Plasma membrane, cytoplasm, dna, ribosomes

Question 4

Describe the major differences between prokaryotic and eukaryotic cells.

Answer 4

Prokaryotes are typically simpler and have no membrane bound organelles

Question 5

Describe the outer layers that might be found on a prokaryotic cell.

Answer 5

Cell wall- made of peptidoglycan for structure and protection
Capsule-attach to surfaces made of polysaccharides

Question 6

What are flagella, pili, and fimbriae?

Answer 6

Fimbriae-attachment
Flagella-movement
Pili-reproduction

Question 7

Which is larger, a prokaryotic or eukaryotic cell?

Answer 7

Eukaryotic

Question 8

Explain how the surface area-to-volume ratio limits cells in their size.

Answer 8

Cells must have enough surface area per volume to keep up with the needs of the cell and move molecules in and out (larger cell=less efficient)

Question 9

Plasma membrane

Answer 9

phospholipid bilayer with embedded proteins and cholesterol that separates the internal cell from its external environment.
Controls the passage of organic molecules, ions, water, and oxygen into and out of the cell.

Question 10

Cell wall

Answer 10

External to the plasma membrane; most eukaryotes made of peptidoglycan; most eukaryotes made of cellulose

Question 11

Cytoplasm

Answer 11

Inside of plasma membrane and nuclear envelope; 70-80% water; contains organelles, cytoskeleton, chemical; metabolic reactions, protein synthesis take place here

Question 12

Nucleus, nucleolus, nucleoplasm, nuclear envelope

Answer 12

Houses genetic material
Dark area of nucleus; aggregates rRNA with proteins to create ribosomal subunits
Cytoplasm in the nucleus
Double-membrane surrounding the nucleus and nucleoplasm

Question 13

Chromatin, chromosomes

Answer 13

Thread-like loosely organized form of genetic material that is present during cell growth and maintenance cycles
Visible, dense, linear forms of chromatin present just prior to cell division

Question 14

Ribosomes

Answer 14

Responsible for protein synthesis; 2 subunits; made in nucleolus

Question 15

Mitochondria

Answer 15

Responsible for making ATP; powerhouse or energy factory of a cell; oval-shaped, double membrane, phospholipid bilayer

Question 16

Chloroplasts, chlorophyll

Answer 16

Carry out photosynthesis; contain chlorophyll, own DNA and ribosomes
Capture light energy

Question 17

Central vacuole

Answer 17

Regulates the cell’s concentration of water

Question 18

Endoplasmic reticulum (rough and smooth)

Answer 18

Protein modification; ribosomes attached to surface
No ribosomes; synthesizes carbohydrates, lipids, and steroids; detoxification of medications and poisons; stores calcium ions

Question 19

Vesicles

Answer 19

Function in storage and transport; can fuse with other membrane systems within the cell

Question 20

Golgi apparatus

Answer 20

Modify, sort, tag, and package proteins and lipids into secretory vesicles to move the products to other places in the cell or out of the cell

Question 21

Lysosomes

Answer 21

Only in animal cells; aid in breakdown of molecules, recycled organelles, and pathogens

Question 22

Cytoskeleton (microfilaments, intermediate filaments, microtubules)

Answer 22

Network of protein fibers to maintain cell shape, secure organelles, allow movement of vesicles, cytoplasm, and whole cell
Cellular movement; actin
Bearing tension; anchor nucleus and other organelles; keratin
Small hollow tubes; largest in diameter; resist cellular compression; flagella, cilia, and centrioles

Question 23

Extracellular matrix

Answer 23

Space outside of the cell that is made of collagen fibers bound with specialized carbohydrates; hold multiple cells together to make tissues; allows for cells to communicate

Question 24

What is ATP?

Answer 24

Adenosine Triphosphate-energy is stored in the chemical bonds and then released for cellular functions that require energy input

Question 25

What is the “Endomembrane System” and how does it work?

Answer 25

A group of membranes and organelles in eukaryotes that work together; modifies, packages, and transports lipids and proteins within and outside of the cell; includes plasma membrane, nuclear envelope, lysosomes, vesicles, ER, and Golgi apparatus