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Anatomy & Physiology Review I > Chapter 3 - The Cellular Level of Organization > Flashcards

Chapter 3 - The Cellular Level of Organization Flashcards

1
Q

What are the 3 Major Parts of a Cell?

A

1- Plasma Membrane (or Cell Membrane)
2- Cytoplasm (Cytosol, Organelles)
3- Nucleus (Chromosomes, Genes)

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2
Q

What is the Plasma Membrane?

A

Plasma Membrane is a flexible sturdy barrier that surrounds the cell and contains Cytosol

Made of a phospholipid bilayer
Has Membrane proteins:
Peripheral proteins
Integral (or Transmembrane) proteins
Glycoproteins
Glycolipids

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3
Q

What are the 2 Types of Membrane Proteins?

A

Integral (or Transmembrane) Protein
Peripheral Protein

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4
Q

What are the Functions of Membrane Proteins?

A

Ion Channel (Integral) - Lets ions in or out
Carrier (Integral) - Transports specific substances in or out
Receptor (Integral) - Recognize specific Ligands and alters cell’s function
Enzyme (Integral and Peripheral) - Catalyzes reaction
Linker (Integral and Peripheral) - Provide structure and stability
Cell Identity Marker (Glycoprotein) - Distinguish self-cells form foreign cells

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5
Q

What is Membrane Fluidity?

A

Membranes are fluid structures
Most membrane lipids and proteins move easily in the bilayer

Cholesterol serves to stabilize the membrane and reduce fluidity

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6
Q

What is Membrane Permeability?

A

Plasma Membranes are selectively permeable

Lipid bilayer always permeable to small, nonpolar, uncharged molecules

Transmembrane proteins act as channels or transporters increasing permeability

Macromolecules are only able to pass by vesicular transport

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7
Q

What is the Electrochemical Gradient across the Plasma Membrane?

A

Electrochemical Gradient is made of Concentration Gradient and Electrical Gradient

Concentration Gradient:
Difference in concentration of a chemical between both sides of plasma membrane

Electrical Gradient:
Difference in concentration of ions between both sides of plasma membrane

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8
Q

What are the 2 types of Transport across the Plasma Membrane?

A

1- Passive Transport:
Simple Diffusion
Facilitated Diffusion
Osmosis

2- Active Transport:
Primary Active Transport
Secondary Active Transport
Vesicular Transport

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9
Q

What is Simple Diffusion?

A

Movement of solutes from areas of high concentration to areas of low concentration

Influenced by;

1- Steepness of concentration gradient
Bigger - faster

2- Temperature
Higher - faster

3- Mass of diffusion substance
Lower - faster

4- Surface area
Bigger - faster

5- Diffusion distance
Shorter - faster

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10
Q

What is Facilitated Diffusion?

A

Transmembrane proteins help solutes that are too polar or too highly charged move through plasma membrane

2 Types:

Channel-Mediated facilitated Diffusion
Specific to unique ion
Usually gated

Carrier-Mediated facilitated Diffusion
Changes shape to open and let specific solute pass

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11
Q

What is Osmosis? And what is Tonicity?

A

Osmosis: the net movement of a solvent (water) through a selectively permeable membrane from an area of high concentration to an area of low concentration

Tonicity: how the solution influences the shape of body cells

ex:
RBC in solution
Isotonic - equal movement of water between RBC/solution, RBC normal
Hypotonic - water enters RBC until bursts, RBC undergoes Hemolysis
Hypertonic - water exits RBC, RBC undergoes Crenation (shrivel)

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12
Q

What is Primary Active Transport?

A

Energy derived from ATP changes shape of transporter protein which pumps a substance across plasma membrane against its concentration gradient (from area of low concentration to area of high concentration)

ex:
Na/K Pump
ATP binds to Na/K pump and promotes binding of Na+ to pump
Binding of Na+ to pump hydrolyze ATP into ADP and P binds to pump
It causes a conformational change of pump
This lets 3 Na+ ions exit into the ECF
At same time, 2 K+ ions bind to pump and release P from pump
This causes another conformational change to the pump
And lets 2 K+ ions into the ICF
Pump back to original shape ready to bind to another ATP

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13
Q

What is Secondary Active Transport?

A

Coupled Active Transport of 2 substances across the membrane using energy from H+ or Na+ concentration gradient to drive substances against their concentration gradient (from low to high)
Maintained by primary active transport pumps

Antiporter: Moves Na+ (or H+) and another substance in opposite directions
Symporter: Moves Na+ (or H+) and another substance in same directions

ex:
Antiporter - Na+ goes into ICF and Ca2+ (or H+) goes out to ECF
Symporter - Na+ goes into ICF and Glucose (or Amino Acid) goes into ICF

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14
Q

What is Receptor-Mediated Endocytosis?

A

Ligand-receptor complexes trigger infolding of a clathrin-coated pit that forms a vesicle containing ligands

Vesicle uncoats, receptors go back to membrane
Vesicle fuses with endosome
Receptors go back to membrane in a transport vesicle
Another transport vesicle takes the ligands and fuses with lysosome
Degradation in lysosome

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15
Q

What is Phagocytosis?

A

Cell Eating
Movement of a solid particle (bacteria, virus, aged/dead cells) into a cell after pseudopods engulf it to form a Phagosome

Phagosome fuses with Lysosome, digest contents by lysosomal enzymes, residual body remaining

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16
Q

What is Bulk Phase Endocytosis (Pinocytosis)?

A

Cell Drinking
Movement of ECF (solutes in ECF) into a cell by infolding of plasma membrane to form a vesicle

Vesicle fuses with Lysosome, digestion by lysosomal enzymes, digested solutes go in ICF

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17
Q

What is Exocytosis?

A

Movement of substances out of a cell in secretory vesicles that fuse with plasma membrane and release their contents in ECF

(Neurotransmitters, Hormones, Digestive Enzymes)

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18
Q

What is Transcytosis?

A

Movement of a substance through a cell as a result of Endocytosis on one side and Exocytosis on the opposite side

(Substances like antibodies across endothelial cells)
(Common route for substances to pass between blood plasma and interstitial fluid)

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19
Q

What is the Plasma Membrane? And what is its Function?

A

Fluid mosaic lipid bilayer (phospholipids, cholesterol, and glycolipids) studded with proteins
Surrounds Cytoplasm

Function:
Protect cellular contents
Makes contact with other cells
Contains channels, transporters, receptors, enzymes, cell-identity markers, and linker proteins
Mediates entry and exit of substances

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20
Q

What is the Cytoplasm? And what is its Function?

A

Cellular contents between plasma membrane and nucleus:
Cytosol and Organelles

Function:
Site of all intracellular activities except those occurring in the nucleus

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21
Q

What is the Organelles? And what is its Function?

A

Specialized structures with characteristic shapes

Function:
Each has a specific function

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22
Q

What is the Cytoskeleton? And what is its Function?

A

Cytoskeleton is a network in the Cytoplasm composed of 3 protein filaments:
Microfilaments
Intermediate filaments
Microtubules

Function:
Maintain shape and general organization of cellular contents
Responsible for cell movements

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23
Q

What is the Cytosol? And what is its Function?

A

Composed of water, solutes, suspended particles, lipid droplets, and glycogen granules

Function:
Fluid in which many of the cell’s reactions occur

24
Q

What is the Centrosome? And what is its Function?

A

Pair of Centrioles plus Pericentriolar Matrix

Function:
Pericentriolar Matrix contains tubulins, which are used for growth of the mitotic spindle and microtubule formation

25
What is the Ribosome? And what is its Function?
Composed of 2 subunits containing ribosomal RNA and proteins May be free in cytosol or attached to Rough Endoplasmic Reticulum Function: Protein synthesis
25
What is the Cilia and Flagella? And what is its Function?
Motile cell surface projections that contain 20 microtubules and a basal body Cilia: made of 9 doublets that have attached proteins called Dynein And 2 central microtubules Function: Cilia: Move fluid across cell's surface Power stroke and Recovery stroke Flagella: Move entire cell Wave movement
26
What is the Endoplasmic Reticulum? And what is its Function?
Membranous network of flattened sacs or tubules Rough ER is covered by ribosomes and is attached to nuclear envelope Smooth ER lacks ribosomes Function: Rough ER: Synthesize glycoproteins and phospholipids that are transferred to cellular organelles, inserted into plasma membrane, or secreted during exocytosis Smooth ER: Synthesize fatty acids and steroids Inactivate or Detoxify drugs Remove phosphate group from glucose-6-phosphate Store and Releases calcium ions in muscle cells
27
What is the Golgi Complex? And what is its Function?
Consists of 3-20 flattened membranous sacs called cisternae Structurally and functionally divided into Cis face (entry), medial cisternae, and Trans face (exit) Function: Cis Face: Accepts proteins from Rough ER Medial Cisternae: Form glycoproteins, glycolipids, and lipoproteins Trans Face: Modifies molecules further Then sorts and packages them for transport to their destinations
28
What is the Lysosome? And what is its Function?
Vesicle formed by the Golgi Complex Contains digestive enzymes Function: Fuses and digests contents from endosomes, phagosomes, and vesicles formed during bulk-phase endocytosis (pinocytosis) Transports final products of digestion into cytosol Digests worn-out organelles (Autophagy), entire cells (Autolysis), and extracellular materials
29
What is the Peroxisome? And what is its Function?
Vesicle containing oxidases (oxidative enzymes) and catalases (decomposes hydrogen peroxide) New peroxisomes bud from preexisting ones Function: Oxidizes amino acids and fatty acids Detoxifies harmful substances such as hydrogen peroxide and associated free radicals
30
What is the Proteasome? And what is its Function?
Tiny barrel-shaped structure that contains proteases (proteolytic enzymes) Function: Degrades unneeded, damaged, or faulty proteins by cutting them into small peptides
31
What is the Nucleus? And what is its Function?
Consists of a nuclear envelope with pores, nucleoli, and chromosomes, which exist as a tangled mass of chromatin in interphase cells Function: Nuclear pores control the movement of substances between the nucleus and cytoplasm Nucleoli produce ribosomes Chromosomes consist of genes that control cellular structure and direct cellular functions
32
What is the Mitochondrion? And what is its Function?
Consists of an external and an internal mitochondrial membrane, cristae, and matrix New mitochondria from from preexisting ones Function: Site of aerobic cellular respiration that produces most of a cell's ATP Play an important early role in Apoptosis
33
What is Transcription?
Transcription occurs in the nucleus and is the process by which genetic information encoded in DNA is copied onto a strand of RNA (mRNA) to direct protein synthesis On DNA there's Promoter, Gene, and Terminator RNA Polymerase attaches to DNA on Gene Build mRNA with Codons following DNA base triplets New mRNA exits RNA Polymerase Introns are snipped and deleted Exons are spliced together Functional mRNA exits through Nuclear pore into Cytoplasm
34
What is Translation?
Translation occurs outside nuclear in cytoplasm Translation is the process of reading the mRNA nucleotide sequence to determine the amino acid sequence of the newly formed protein mRNA attached to small subunit of ribosome Initiator tRNA attaches to start codon on mRNA Large and small ribosomal subunits join to form functional ribosome Initiator tRNA fits into P Site Anticodon of incoming tRNA pairs with next mRNA codon at A Site Amino acid on tRNA at P Site form peptide bond with amino acid on A Site The 2-peptide protein created from the formation of peptide bond becomes attached to tRNA on A Site Ribosome shifts by one codon, tRNA previously on P Site enters E Site and is released from ribosome, tRNA previously at A Site is now at P Site Protein synthesis stops when ribosome reaches a stop codon on mRNA
35
What is Replication of DNA?
DNA makes an exact copy of itself DNA splits at Replication Fork New strand is made out of each Old strand by DNA Polymerase Forming 2 double helices made of one new and one old strand each
36
What is Cell Division?
Process by which cell reproduce itself Cell Cycle: G1 Phase S Phase G2 Phase Mitotic Phase - PMAT Possible G0 Phase Interphase = G1, S, and G2
37
What is Mitosis?
Mitosis occurs when nucleus of cell divides Results in distribution of 2 sets of chromosomes into 2 separate nuclei Divided into 4 steps (PMAT): Prophase Metaphase Anaphase Telophase
38
What is Prophase?
Chromatin condenses into chromosomes Nuclear membrane disappears Centrosomes move to opposite poles Late Prophase: Mitotic spindle (microtubules) form and attach to chromosomes at Kinetochore
39
What is Metaphase?
Centromeres of chromosomes line up at the metaphase plate
40
What is Anaphase?
Centromeres of chromosomes split Sister chromatids move towards opposite poles of the cell Late Anaphase: Cleavage furrow forms
41
What is Telophase?
Mitotic spindle dissolves Chromosomes regain their chromatin appearance New nuclear membrane forms
42
What is Cytokinesis?
Cleavage furrow grows Eventually cytoplasm of parent cell fully splits Forming 2 identical cells Interphase starts when this is complete
43
What is Interphase?
Period between cell divisions Chromosomes not visible under light microscope
44
What is G1 Phase of Interphase?
Cell duplicates organelles Replication of chromosomes begin If stay too long called G0 Phase
45
What is S Phase of Interphase?
Replication of DNA and centrosomes
46
What is Mitotic Phase?
Parent cell produces identical cells with identical chromosomes Chromosomes visible under light microscope
47
How is Meiosis I Prophase I different than Mitosis?
Tetrads form by synapsis of sister chromatids of homologous chromosomes Crossing-over between non-sister chromatids
48
How is Meiosis I Metaphase I different than Mitosis?
Pairing of homologous chromosomes at metaphase plate instead of single chromosomes
49
How is Meiosis I Anaphase I different than Mitosis?
Separation of homologous chromosomes instead of sister chromatids (sister chromatids remain together here)
50
How is Meiosis I Telophase I different than Mitosis?
2 non-identical cells formed
51
What is Meiosis II?
Meiosis II looks similar to Mitosis, but results in 4 haploid cells that are non-identical
52
What is the Resting membrane Potential?
1- K+ diffuses out of cell down their concentration gradient via leakage channels, making inner plasma membrane face negatively charged 2- K+ also moves into the cell because attracted to negatively charged inner plasma membrane face 3- Negative membrane potential (-90mV) established when K+ moving out equals K+ moving into cell
53
How does Cell Communication work?
1- Ligand (1st messenger, could be neurotransmitter or hormone) binds to receptor Receptor changes shape and activates 2- Activated receptor binds to a G protein and actives it G protein changes shape and release GDP and bind to GTP (energy source) 3- Activated G protein activates or deactivates an Effector protein Effector protein changes shape 4- Activated Effector enzymes catalyze reactions that produce 2nd messenger (like Cyclic AMP - cAMP, or Ca2+) 5- 2nd messenger activate other enzymes or ion channels cAMP usually activates protein Kinase enzymes 6- Kinase enzymes activate other enzymes Kinase enzymes transfer phosphate groups from ATP to specific proteins and activate a series of other enzymes that trigger various metabolic and structural changes in the cell
54
What is a Microfilament?
Strands made of spherical protein subunits called Actin
55
What is an Intermediate Filament?
Tough, insoluble protein fibers constructed like woven ropes composed of Tetramer (4) Fibrils
56
What is a Microtubule?
Hollow tubes of spherical protein subunits called Tubulin

Anatomy & Physiology Review I (30 decks)

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