Chapter 3 Flashcards

1
Q

What are the common cellular functions?

A
Cell metabolism / energy use
Synthesis of molecules
Communication
Reproduction
Inheritance
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2
Q

What are the functions of the plasma membrane?

A

Boundary - separates intracellular/extracellular

Determines what moves into/out of cells

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3
Q

What is membrane potential?

A

The charge difference across the plasma membrane. Outside is more positively charged than inside due to gathering of ions on plasma membrane.

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4
Q

Describe the glycocalyx.

A

A collection of glycolipids (carb + lipid), glycoproteins (carb + protein) and carbohydrates on the outer surface of the PM (plasma membrane).

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5
Q

What is the lipid bilayer?

A

A double layer of phospholipid molecules. Have polar (hydrophilic) head and nonpolar (hydrophobic) tail.

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6
Q

What does hydrophilic mean?

A

Water loving. Heads of lipids are positively charged and exposed to extracellular and intracellular fluids of cell.

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7
Q

What does hydrophobic mean?

A

Water fearing. Tails face the interior of the plasma membrane.

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8
Q

What is cholesterol’s function inside the plasma membrane?

A

Interspersed among phospholipids and accounts for 1/3 total lipids in plasma membrane.

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9
Q

What does the fluid nature of the phospholipid bilayer allow for?

A

Distribution of molecules in the membrane.
Phospholipids can automatically reassemble with damage.
Membranes can fuse.

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10
Q

What are the two major types of membrane proteins?

A

Integral (intrinsic) - penetrates deeply into lipid bilayer

Peripheral (extrinsic) - attached to either inner/outer surfaces of lipid bilayer

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11
Q

What are the five types of membrane proteins?

A
Marker molecules
Attachment proteins
Transport proteins
Receptor proteins
Enzymes
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12
Q

Where are marker molecules located? What is their function?

A

Located on cell surface.

Allows cells to identify other molecules/cells. Usually glycoproteins or glycolipids

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13
Q

What is the function of attachment proteins?

A

Allow cells to attach to each other or to extracellular molecules.

Cadherins: cells to other cells
Integrins: cellular membrane proteins to extracellular molecules

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14
Q

What are the three types of channel proteins?

A

Non-gated: always open

Ligand-gated: open/closed in response to chemical signals
Voltage-gated: open/close in response to change in charge across plasma membrane

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15
Q

What are carrier proteins?

A

Transporters.
Move molecules from one side of plasma membrane to the other by changing shape.

Uniporters - moves one particle
Symporters - 2 particles in same direction
Antiporters - 2 particles in opposite direction

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16
Q

What are the four ways that molecules can pass through the plasma membrane?

A

Diffusion
Osmosis
Mediated transport
Active transport

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17
Q

What is the difference between diffusion and osmosis?

A

Diffusion - movement of solutes from high concentration to low concentration.

Osmosis - diffusion of solvent (water) across a selectively permeable membrane (allows water but not all solutes in water).

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18
Q

What is osmotic pressure?

A

The force required to prevent water from moving across a SP membrane.

Isosmotic - same concentration of solutes/same pressure

Hyperosmotic - greater concentration of solute particles, higher osmotic pressure.

Hypoosmotic - lesser concentration of solute particles, lower osmotic pressure (more dilute solution)

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19
Q

What are the three types of tonicity of cells?

A

Isotonic - cell placed in solution, neither shirnks nor swells

Hypertonic - cell placed in, water moves OUT, cell shrinks (crenation)

Hypotonic - cell placed in, water moves INTO cell and cell bursts (lysis)

IMPORTANT FOR FLUID ADMINISTRATION IN DEHYDRATED PATIENTS.

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20
Q

What is mediated transport?

A

Process by which transport proteins mediate or assist, movement of large water soluble molecules or electrically charged molecules/ions across plasma membrane.

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21
Q

What are the three characteristics of mediated transport?

A

Specificity - each transport protein binds to/transports only one ion/molecule

Competition - result of similar molecules binding to transport protein

Saturation - rate of movement of molecules across membrane is limited by number of available transport proteins

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22
Q

What is the difference between passive and active transport?

A

Passive transport - cell does not expend metabolic energy. (diffusion, osmosis, facilitated diffusion)

Active transport - cell expends metabolic energy. (can move substances from low to high with ATP and high to low)

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23
Q

What is facilitated diffusion?

A

A carrier-mediated or channel-mediated passive membrane transport process that moves substances into or out of cells from high to low. Does not require ATP.

24
Q

What is secondary active transport?

A

Active transport of an ion out of a cell from low to high concentration. The tendency for the inos to move back provides energy necessary to move a different ion or other molecule into the cell.

Moves by symport or antiport.

Sodium/Potassium or glucose movement.

25
Q

What is the difference between endocytosis and exocytosis?

A

Endocytosis - uptake of material into cell by formation of a vesicle. PM wraps around particle/droplet and fuses so the membrane “eats” the particle/droplet.

Exocytosis - secretions that accumulate within vesicles cause these vesicles to fuse to the PM and the vesicle contents are expelled from cell.

26
Q

What is the cytoplasm?

A

Cellular material outside the nucleus but inside plasma membrane. Composed of cytosol, cytoskeleton, cytoplasmic inclusions and organelles.

27
Q

What is cytosol?

A

Fluid portion of cytoplasm. Contains cytoskeleton/cytoplasmic inclusions.

28
Q

What is the cytoskeleton?

A

Supports the cell and holds nucleus and other organelles in place.

Responsible for allowing movement of cell organelles and changes in cell shape.

29
Q

What is the cytoskeleton made of?

A

Microtubules - internal scaffolding, assist with transport/cell division

Actin filaments - offers support, supports microvilli, helps with contractibility/movement

Intermediate filaments - offer mechanical strength to cells

30
Q

What are cytoplasmic inclusions?

A

Aggregates of chemicals either produced or taken in by cell. Includes chemicals for energy storage, pigmentation or for transporting other molecules.

31
Q

What is the nucleus?

A

Large, membrane-bound structure near center of cell. Houses majority of DNA - organized into structures called chromosomes.

Nucleoplasm - cytoplasm of nucleus
Nuclear envelope - PM of nucleus
Nucleolus - nucleus of nucleus

32
Q

What is a chromosome?

A

Fibrous structures of DNA and protein called chromatin.

Chromatids joined together by centromere and become a chromosome.

33
Q

What is the ribosome?

A

Site of protein synthesis.

FREE or ATTACHED (to ER)

34
Q

What is the endoplasmic reticulum?

A

(makes packages)

Consists of broad, flat interconnected sacs/tubules - cisternae - separate from rest of cytoplasm.

Rough ER - ribosomes attached; protein production
Smooth ER - no ribosomes; lipid production

35
Q

What is the golgi apparatus?

A

(ships packages)

Packaging/distribution center for proteins/lipids manufactured by ER.

Create lysosomes - membrane bound vesicles that may include hydrolytic enzymes that function as digestive enzymes.

36
Q

What is the mitochondria?

A

POWERHOUSE!

Provides energy for cell with ATP synthesis.

Inner foldings - cristae…make up the matrix.
Mitochondria increase in # when cell energy requirements increase.

37
Q

What are the centrioles and spindle fibers?

A

Located close to nucleus in centrosome - specialized zone for microtubule formation.

Centrioles - move to poles before cell division and organize spindle cell fibers.

Spindle cell fibers - bind to chromosomes to facilitate movement of chromosomes toward two centromeres.

38
Q

What are the cilia?

A

Structures that project from the surface of cells and are capable of movement.

1-1000’s per cell.

39
Q

What is the flagella?

A

Longer cilia - sperm cells are only human cells that possess flagella. One per cell.

40
Q

What are the microvilli?

A

Extension of plasma membrane that increases surface area. Not used for movement. Much smaller than cilia.

41
Q

What are genes?

A

Functional units of hereditary (transmission of traits from parents to offspring)

42
Q

What is gene expression?

A

Production of proteins from information stored in DNA.

43
Q

What is gene regulation?

A

All nucleated cells (except germ cells) have full complement of DNA. During development, differentiation occurs and some segments are turned off.

44
Q

What is transcription?

A

“copying the recipe”

Synthesis of types of RNA based on DNA sequence. One DNA strand serves as template for transcription.

45
Q

What is translation?

A

“making the cake”

Synthesis of a protein at the ribosome in response to codons of mRNA.

46
Q

Explain how genetic code works.

A

The sequence of bases on a DNA strand.

Bases (letters)
Codons (three letter words)
Protein (words into sentences)
Chromosomes (sentences into book)
Genome (books of library)
47
Q

What are the phases of a cell’s life?

A

Interphase - 90% of time

Mitosis - 10% of time

48
Q

What happens in interphase?

A

G1 (1st gap phase) - cell carries out routine metabolic activities
S (synthesis phase) - new DNA synthesized
G2 (2nd gap phase) - cell prepares for division

49
Q

What happens in mitosis?

A

Prophase: chromatin condenses and forms mitotic chromosomes
Metaphase: chromosomes align near center
Anaphase: chromatids separate
Telophase: nuclear envelope forms, two separate nuclei

50
Q

What is cytokinesis?

A

Occurs after mitosis - separation of cytoplasm between two new cells.

51
Q

What is meiosis?

A

A type of cell division specialized for sexual reproduction.

One cell undergoes two divisions to produce four genetically different daughter cells. One homolog from each homologous pair.

Diploid (2 chromosomes: 2n) - first division - 2 cells
Haploid (1 chromosome: 1 n) - second division - 4 cells - EGG/SPERM

52
Q

What is the difference between a genetic disorder and a birth defect?

A

Genetic disorder is an abnormality in DNA. A birth defect is due to developmental problems.

53
Q

What causes birth defects?

A

Teratogens (radiation, drugs, alcohol, etc.)

Do not cause abnormalities in DNA.

54
Q

What causes genetic disorders?

A

Mutagenes - agents that cause mutations

Oncogenes - DNA replication on steroids (some genetic and some from exposure to carcinogens)

55
Q

What is a carcinogen?

A

Anything that increases the risk of cancer.