a&p1 quiz 2

List four functions of human cells.

1. Maintain integrity and shape of a cell (both the plasma membrane and the internal contents)

2. Obtain nutrients and form chemical structures

3. Dispose of wastes

4. Undergo cell division

What are the three common characteristics of all cells?

Plasma membrane, nucleus, and cytoplasm

What is the scientific term for the boundary between the intra- and extracellular environments?

Plasma membrane

Name six membrane proteins and describe their functions.

Integral membrane proteins:

1. Transporters: move substances across membrane

2. Receptors: respond to neurotransmitters and hormones

3. Identity markers: identify “self” to immune cells

Peripheral Membrane proteins:

1. Enzymes: catalyze chemical reactions

2. Anchoring sites: secure cytoskeleton to membrane

3. Linkers: cell-to-cell attachment

Name two membrane lipids and describe their function.

Cholesterol: Lipoprotein, strengthen membrane and stabilize against temperature extremes

Glycolipids: Lipids with attached carbohydrate groups, maintain membrane stability, located on outer phospholipid region only

Where is DNA housed? In what form is it found during protein synthesis? Cellular division?

Found in the Nucleus

During protein synthesis: Chromatin, unwound strands of DNA

During cellular division: chromosomes, coiled DNA

Name three membrane junctions and discuss the function of each.

Tight junctions: protein “stitches” anchoring neighboring cells, prevent substances form passing between cells, require material to move THROUGH instead of BETWEEN

Desmosomes: stronger protein connections that link adjacent cytoskeletons

Gap junctions: form tiny, fluid-filled tunnels between the insides of two cells, provide direct passageway for IONS to travel BETWEEN cells

What are the two components of cytoplasm?

Cytosol: Fluid medium within cell (water/chemicals), support organelles, site of millions of cellular chemical reactions/second

Organelles: “little organs,” perform the work of the cell, eight different organelles, each w/ specific function

Which organelle is the “powerhouse” of the cell?

Mitochondriaaaaaa!!!!!!!!

Which organelle is responsible for protein synthesis?

Ribosome duhhh

What makes the rough ER (endoplasmic reticulum) rough?

Ribosomes make it rough

Discuss the function of the Golgi apparatus

Sorts and packs macromolecules for cell maintenance, repair and transport, and secretion, formation of secretory vesicles, release contents outsides of cell

Which organelle acts as a destroy and clean-up crew?

Lysosomes

Centrosomes are made up of what structures? In which process are they involved?

Made up of two centrioles, function in cellular division, reorganize the cytoskeleton to move chromosomes to ensure each daughter cell receives the appropriate number of chromosomes

Proteasomes are responsible for “quality control” over which macromolecule?

Protein

Which system do cilia bring to mind?

Respiratory system

Which system do Villi bring to mind?

Digestive system

Which system do Flagella bring to mind?

Reproductive system

Which structure forms a protein scaffolding within each cell? What functions does it perform?

Cytoskeleton, function: cell shape, organization, movement, cell division/reproduction

How does O₂ diffuse into a cell and CO₂ diffuse out of a cell?

Through simple diffusion

Discuss the difference by channel-mediated facilitated diffusion and carrier-mediated diffusion.

Channel-mediated: ions move down their concentration gradient through water-filled channels

Carrier-mediated: carrier proteins change shape to transport small polar molecules across the plasma membrane

What is osmosis?

The movement of water, NOT SOLUTES, passive movement of water through semipermeable membrane (phospholipid bilayers)

What occurs to the tonicity of a cell when it is placed into an isotonic, a hypotonic, or a hypertonic solution?

Isotonic solution: has the same relative concentration of solutes and water as the cell’s cytosol, same amount of water outside and inside the cell

Hypotonic solution: lower concentration of solutes and a higher concentration of water than the cell’s cytosol, too much water goes into the cell, causes hemolysis in blood cells, cells explode

Hypertonic solution: higher concentration of solutes and lower concentration of water than the cell’s cytosol, water moves out of the cell, causes shrinkage in cells (crenation)

What transport process involved in the movement of Na⁺down its gradient is used to power another substance up its gradient?

Secondary active transport

What is meant by “cell eating” and “cell drinking”?

Cell drinking: pinocytosis, ingestion of liquid into a cell via invaginations

Cell eating: phagocytosis, ingestion of microbes or debris into a cell via pseudopods

Both are types of vesicular transport: endocytpsis

Define “resting membrane potential.”

The electrical charge difference at plasma membrane, difference in charge when the cell is at rest, unequal distribution of ions/molecules across plasma membrane, inside cell always negative, outside is positive

Describe ligand-receptor signaling. What changes might occur as a result of this process?

Most cell communication occurs through this process, chemical messengers released by one cell to signal either itself or a different cell, changes: channel-linked receptors, g-protein-coupled receptors, enzyme-linked receptors