Cell Basics (Lecture 13)

Question 1

What does it take to make a cell?

1. INFORMATION

(Dynamic)

What do all cells possess? What is its purpose?

Answer 1

All cells possess DNA, the hereditary material of genes, and RNA, that provide the information required to build the primary machinery of the cell.

Question 2

What do red blood cells lack?

Answer 2

• Red Blood Cells lack nuclei, do not contain DNA, and cannot synthesize RNA - consequently, they do not divide and have limited repair capabilities.
• This feature of RBCs evolved to maximize hemoglobin carrying capacity.

Question 3

When did LIFE start?

CHEMISTRY

What is The Miller-Urey Experiment?

Answer 3

The Miller-Urey Experiment (1952)

A chemical experiment that simulated the conditions thought to exist on the early Earth and to test the chemical origin of life under those conditions.

Question 4

CHEMISTRY

What is the Oparin/Haldane hypothesis?

Answer 4

Conditions on the primitive Earth favored chemical reactions that synthesized more complex organic compounds from simpler inorganic precursors.

Question 5

What does it take to make a cell? (3 things)

Answer 5

1. Information (dynamic)
2. Chemistry (matter and energy)
3. Compartments

Question 6

COMPARTMENTS

What is it usually defined as?

Give 3 examples of cellular compartments

Answer 6

Usually defined by a lipid membrane layer

Examples of cellular compartments:

• cell nucleus
• mitochondria
• chloroplasts

Question 7

COMPARTMENTS

What are the two fundamental roles of compartments?

Answer 7

Fundamental Roles of Compartments:

• Establish physical boundaries that enable the cell to carry out different metabolic activities.
• Generate a micro-environment to spatially and temporally regulate biological processes.

*selective permeability*

HOMEOSTASIS

Question 8

What is the cell theory?

Answer 8

1. The cell is the structural unit of life (Schleiden & Schwann (1839))
2. All organisms are composed of 1 or more cell types (Schleiden & Schwann (1839))
3. Cells can arise only by the division of a pre-existing cell (1855)

Question 9

What is the cell?

Answer 9

The cell is the fundamental unit of life

Question 10

What are the 9 basic properties of cells?

Answer 10

1. Highly complex and organized
2. Activity controlled by a genetic program
3. Can reproduce - make copies of themselves
4. Assimilate and utilize energy
5. Carry out many chemical Reactions - Enzymes
6. Engage in mechanical activities
7. Respond to stimuli
8. Capable of self-regulation
9. They evolve

Question 11

Prokaryotic Cell vs Eukaryotic Cell

What is the difference?

Answer 11

The difference between prokaryotes and eukaryotes is an important distinction

among groups of organisms.

Question 12

What are prokaryotes?

Answer 12

Prokaryotes were the only form of life on Earth for millions of years until more

complex eukaryotic cells came into being through the process of evolution.

Question 13

Typical features of a bacterial cell

Answer 13

1. pilus
2. capsule
3. cell wall
4. plasma membrane
5. nucleoid (DNA)
6. cytoplasm
7. ribosomes
8. flagellum

Question 14

Prokaryotic Cell vs Eukaryotic Cell

Answer 14

1. Nucleus
2. Plasma Membrane
3. Nucleoid

Left cell: Prokaryotic cell

Right cell: Eukaryotic cell

Question 15

Typical features of an animal cell

The function of the nucleus?

Answer 15

The nucleus is the storehouse for the cells genetic information and the site for RNA synthesis

Question 16

Typical features of an animal cell

The function of the mitochrondria?

Answer 16

Mitochondria produce most of the ATP that serves as the energy currency of the cell

Question 17

Typical features of an animal cell

The function of the plasma membrane?

Answer 17

The plasma membrane is composed of phospholipids and proteins and regulates the passage of materials into and out of the cell

Question 18

Typical features of an animal cell

The function of the cytoskeleton?

Answer 18

The cytoskeleton is the network of protein filaments and other associated proteins that provide the cell with an internal structural framework

Question 19

Typical features of an animal cell

The function of the endoplasmic reticulum?

Answer 19

The endoplasmic reticulum is involved in both protein and lipid synthesis

Question 20

Typical features of an animal cell

The function of the Golgi apparatus?

Answer 20

The Golgi apparatus modifies and sorts proteins and lipids as they move to their final destinations in or out of the cell

Question 21

Typical features of an animal cell

The function of the peroxisomes?

Answer 21

Peroxisomes break down specific organic molecules, such as fatty acids, and synthesize other organic molecules, such as cholesterol and some types of phospholipids.

Question 22

Typical features of the plant cell

The function of the plant cell wall?

Answer 22

The plant cell wall is a rigid barrier composed of polysaccharides

Question 23

Typical features of the plant cell

The function of the chloroplasts?

Answer 23

Chloroplasts enable plant cells to harness the energy of sunlight to synthesize sugars

Question 24

Typical features of the plant cell

The function of the plasmodesmata?

Answer 24

Plasmodesmata connect neighboring plant cells

Question 25

Typical features of the plant cell The function of the vacuoles?

Answer 25

Vacuoles are organelles that contribute to the structural rigidity of plants by maintaining turgor pressure against cell walls

Question 26

Animal vs. Plant What are numbers 1, 2, 3, 4, 5, and their functions?

Answer 26

1. **Plasma Membrane** controls the movement of molecules in and out of the cell and functions in cell-cell signaling and cell adhesion (Both) 2. **Mitochondria** which are surrounded by a double membrane, generate ATP by oxidation of glucose and fatty acids (Both) 3. **Lysosomes**, which have an acidic lumen, degrade material internalized by the cell and worn-out cellular membranes and organelles (Animal) 4. **Nuclear envelope**, a double membrane, encloses the contents of the nucleus; the outer nuclear membrane is continuous with the rough ER (Both) 5. **Nucleolus** is a nuclear subcompartment where most of the cell's rRNA is synthesized (Both)

Question 27

Animal vs. Plant What are numbers 6, 7, 8, 9, 10, and their functions?

Answer 27

6. **Nucleus** is filled with chromatin composed of DNA and proteins; site of mRNA and tRNA synthesis (Both) 7. **Smooth endoplasmic reticulum (ER)** contains enzymes that synthesize lipids and detoxify certain hydrophobic molecules (Both) 8. **Rough endoplasmic reticulum (ER)** functions in the synthesis, processing, and sorting of secretes proteins, lysosomal proteins, and certain membrane proteins (Both) 9. **Golgi complex** processes and sorts secreted proteins, lysosomal proteins, and membrane proteins synthesized on the rough ER (Both) 10. **Secretory vesicles** store secreted proteins and fuse with the plasma membrane to release their contents (Both)

Question 28

Animal vs. Plant What are numbers 11, 12, 13, 14, and their functions?

Answer 28

11. **Peroxisomes** contain enzymes that break down fatty acids into smaller molecules used for biosynthesis and also detoxify certain molecules (Both) 12. **Cytoskeletal fibers** form networks and bundles that support cellular membranes, help organize organelles, and participate in cell movement (Both) 13. **Microvilli** increase surface area for absorption of nutrients from the surrounding medium (Animal) 14. **Cell wall,** composed largely of cellulose, helps maintain the cell's shape and provides protection against mechanical stress (Plant)

Question 29

Animal vs. Plant What are numbers 15, 16, 17, and their functions?

Answer 29

15. **Vacuole** stores water, ions, and nutrients degrade macromolecules, and functions in cell elongation during growth (Plant) 16. **Chloroplasts,** which carry out photosynthesis, are surrounded by a double membrane and contain a network of internal membrane-bounded sacs (Plant) 17. **Plasmodesmata** are tubelike cell junctions that span the cell wall and connect the cytoplasms of adjacent plant cells (Plant)

Question 30

Click to see an animal cell and some of its parts

Answer 30