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Anatomy & Physiology 1 Midterm > Chapter 3 > Flashcards

Chapter 3 Flashcards

1
Q

List the three main parts of a cell and explain their functions.

A
  1. Plasma membrane- forms the cell’s flexible outer surface, separating the cell’s internal environment from the external environment
  2. Cytoplasm- consists of all the cellular contents between the plasma membrane and the nucleus. Has 2 components; the cytosol and organelles.
  3. The Nucleus- Large organelle that houses most of a cell’s DNA.
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2
Q

Define Chromatin.

A

A condensed form of DNA in the nucleus.

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3
Q

Describe what makes up the plasma membrane.

A

The plasma membrane consists of a phospholipid bilayer, cholesterol, and proteins. There are phospholipids that contain a hydrophilic head and a hydrophobic tail. Cholesterol can be seen attached on both sides of the bilayer. There are integral proteins which are amphipathic and Peripheral proteins which are hydrophilic and outside only.

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4
Q

What are the different types of membrane proteins?

A
  1. ion channel
  2. Carrier
  3. Receptor
  4. Enzyme
  5. Linker
  6. Cell identity marker
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5
Q

What stabilizes the membrane’s fluidity?

A

Cholesterol

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6
Q

Describe selectively permeable

A

The lipid bilayer is always permeable to small, nonpolar, uncharged molecules. Transmembrane proteins act as channels or carriers to increase the permeability of the membrane. Some macromolecules pass through via vesicular transport.

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7
Q

What makes up an electrochemical gradient?

A
  1. A concentration gradient is the difference in the concentration of a chemical between both sides of the plasma membrane.
  2. An electrical gradient is the difference in concentration of ions between one side of the plasma membrane.

Together these make up an electrochemical gradient.

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8
Q

What are some transport processes that do not require energy?

A

Simple diffusion
Facilitated diffusion
Osmosis
(Passive processes)

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9
Q

What are some transport processes that require energy?

A

Primary active transports
Secondary active transport
Vesicular transport
(Active processes)

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10
Q

What can influence diffusion?

A
  1. Steepness of the concentration gradient.
  2. Temperature
  3. Mass of diffusing substance.
  4. Surface area
  5. Diffusion distance.
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11
Q

What is the purpose of Facilitated diffusion?

A

Transmembrane proteins help solutes that are too polar or too highly charged, move through the lipid bilayer.

There are 2 processes;
Channel-mediated facilitated diffusion.
Carrier-mediated facilitated diffusion.

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12
Q

Describe Osmosis.

A

movement of a solvent through a selectively permeable membrane from an area of high concentration to an area of low concentration.

Water is moved due to hydrostatic pressure. Applied pressure = osmotic pressure.

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13
Q

Describe the possible tonicity of solutions.

A

Isotonic- same concentration.
Hypotonic- a solution that has a lower concentration of solute than the cytosol inside the RBCs
Hypertonic- has a higher concentration of solutes than does the cytosol inside RBCs

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14
Q

Describe Primary active transport

A

Energy derived from ATP changes the shape of a transporter protein. Which pumps a substance across a plasma membrane against its concentration gradient. (Involved in muscle and nerve cells)

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15
Q

Describe secondary active transport

A

Energy stored in either hydrogen or sodium concentration gradient is used to drive other substances against their own concentration gradients.

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16
Q

What is the difference between Antiporters and Symporters?

A

Antiporters- move two substances in opposite directions across the membrane.
Symporters- move two substances in the same direction

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17
Q

Describe the process of Receptor-mediated endocytosis.

A
  1. Binding- n LDL particle that contains cholesterol binds to a specific receptor in the plasma membrane to form a receptor. Which causes the plasma membrane to fold inwards.
  2. Vesicle formation- a small piece of the membrane pinches off
  3. Uncoating- the clathrin-coated vesicle loses its clathrin coat to become an uncoated vesicle.
  4. Fusion with endosome- Within an endosome, the LDL particles separate from their receptors.
  5. Recycling of receptors to plasma membrane- form transport vesicles that return the receptors to the plasma membrane
  6. Degradation in lysosome- enzymes break down the large protein and lipid molecules of the LDL particle into amino acids, fatty acids, and cholesterol. The cell uses cholesterol for rebuilding its membranes and for the synthesis of steroids, such as estrogen.
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18
Q

Describe the process of phagocytosis

A

Form of endocytosis; in which the cell engulfs large solid particles, such as worn-out cells, whole bacteria, or viruses. Two main types of phagocytes are macrophages, located in many body tissues, and neutrophils, a type of white blood cell. Pseudopods surround the particle outside the cell and use the membranes to engulf it. Then it turns into a phagosome(vesicle) where then the fusion of lysosome and phagosome occurs. Digestion by lysosomal enzymes is left in the residual body and any undigested material is carried out by exocytosis or remains stored in the cell.

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19
Q

Describe the process of Pinocytosis

A

tiny droplets of extracellular fluid are taken up.all solutes dissolved in the extracellular fluid are brought into the cell. During bulk-phase endocytosis, the plasma membrane folds inward and forms a vesicle containing a droplet of extracellular fluid. The vesicle then pinches off from the plasma membrane into the cytosol. The fusion of the lysosome and the vesicle occurs. Resulting in smaller molecules by digestion of the lysosomal enzymes.

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20
Q

Describe Exocytosis

A

releases materials outside of the cell into the extracellular fluid. All cells carry out exocytosis, but it is especially important in two types of cells: (1) secretory cells that liberate digestive enzymes, hormones, mucus, or other secretions, and (2) nerve cells that release substances called neurotransmitters.

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21
Q

Describe Transcytosis

A

combination of endocytosis and exocytosis used to move substances from one side of a cell, across it, and out the other side.

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22
Q

What substances can be transported via simple diffusion?

A

Nonpolar; oxygen, co2, and nitrogen gases.
Polar; water, urea, and small alcohols.

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23
Q

What substances can be transported via facilitated diffusion?

A

Polar or charged solutes; glucose, fructose, galactose, some vitamins, and ions such as K+, Cl-, Na+, and Ca2+.

24
Q

What substance can be transported via Osmosis?

A

Water in living systems.

25
Q

What substance can be transported via Primary active transport?

A

Na+, K+, Ca2+, H+, Cl-, and other ions.

26
Q

What substance can be transported via Secondary Active transport?

A

Antiport; Ca2+, H+ out of cells.
Symport; glucose, amino acids into cells.

27
Q

What substance can be transported via Receptor-mediated endocytosis?

A

Ligands: LDL, some vitamins, hormones, and antibodies.

28
Q

What substance can be transported via Phagocytosis?

A

Bacteria, Viruses, and aged or dead cells.

29
Q

What substance can be transported via Bulk-Phase endocytosis (Pinocytosis)?

A

Solutes in extracellular fluid.

30
Q

What substance can be transported via Exocytosis?

A

Neurotransmitters, hormones, and digestive enzymes.

31
Q

What substance can be transported via Transcytosis?

A

Antibodies, across endothelial cells. Substances to pass between blood plasma and interstitial fluid.

32
Q

Describe the structure and function of the Cytoplasm.

A

consists of all the cellular contents between the plasma membrane and the nucleus, and has two components: (1) the cytosol and (2) organelles.

33
Q

What is Cytosol?

A

fluid portion of the cytoplasm also known as interstitial fluid. The site of many chemical reactions required for a cell’s existence.

34
Q

What is the cytoskeleton?

A

The network in the cytoplasm is composed of three protein filaments: Microfilaments, intermediate filaments, and microtubules.
Maintains shape and general organization of cellular contents.

35
Q

What are organelles?

A

structures within the cell that have characteristic shapes, and they perform specific functions in cellular growth, maintenance, and reproduction.

36
Q

Describe the structure and function of Microfilaments.

A

The thinnest element of the cytoskeleton is composed of the proteins actin and myosin and are most prevalent at the edge of a cell. They help generate movement and provide mechanical support. Involved in muscle contraction, cell division, and cell locomotion, such as occurs during the migration of embryonic cells during development, and the invasion of tissues by white blood cells to fight infection.

Microfilaments also provide mechanical support for cell extensions called microvilli.

37
Q

Describe the structure and function of Intermediate filaments.

A

found in parts of cells subject to mechanical stress; they help stabilize the position of organelles such as the nucleus and help attach cells to one another.

38
Q

Describe the structure and function of Microtubules.

A

The largest of the cytoskeletal components are long, unbranched hollow tubes composed mainly of the protein tubulin. Microtubules help determine cell shape. They also function in the movement of organelles such as secretory vesicles, of chromosomes during cell division, and of specialized cell projections, such as cilia and flagella.

39
Q

Describe the structure and function of Centrosomes.

A

A pair of centrioles plus a pericentriolar matrix, which contains tubulins, which are used for the growth of the mitotic spindle and microtubule formation.

40
Q

Describe the structure and function of Cilia and Flagella.

A

Motile cell surface projections that contain 20 microtubules and a basal body.
Cilia: moves fluids over the cell’s surface
Flagella: moves entire cell.

41
Q

Describe the structure and function of Ribosomes

A

sites of protein synthesis. Has a high content of one type of ribonucleic acid, but each ribosome also includes more than 50 proteins.

42
Q

Describe the structure and function of the Endoplasmic Reticulum

A

Network of membranes in the form of flattened sacs or tubules.

Rough ER: The outer surface of rough ER is studded with ribosomes, the sites of protein synthesis. Proteins synthesized by ribosomes attached to rough ER enter spaces within the ER for processing and sorting. Rough ER produces secretory proteins, membrane proteins, and many organellar proteins.

Smooth ER: synthesize fatty acids and steroids, such as estrogens and testosterone. Release glucose into the bloodstream and inactivate or detoxify lipid-soluble drugs or potentially harmful substances, such as alcohol, pesticides, and carcinogens. A smooth ER enzyme removes the phosphate group from glucose-6-phosphate, which allows the “free” glucose to enter the bloodstream. In muscle fibers, the calcium ions (Ca2+) that trigger contraction are released from the sarcoplasmic reticulum, a form of smooth ER.

43
Q

Describe the structure and function of the Golgi complex

A

It consists of 3 to 20 saccules. Golgi complexes are more extensive in cells that secrete proteins, a clue to the organelle’s role in the cell. The entry (cis) face is a saccule that faces the rough ER. The concave exit (trans) face is a saccule that faces the plasma membrane. Sacs between the entry and exit faces are called intermediate saccules.

Different enzymes in the entry, and exit saccules of the Golgi complex permit each of these areas to modify, sort, and package proteins into vesicles for transport to different destinations. The entry face receives and modifies proteins produced by the rough ER. The intermediate saccules add carbohydrates to proteins to form glycoproteins and lipids to proteins to form lipoproteins. The exit face modifies the molecules further and then sorts and packages them for transport to their destinations.

44
Q

Describe the structure and function of Lysosome

A

Membrane-enclosed vesicles that form from the Golgi complex. Fuses with and digests contents of endosomes, phagosomes, and vesicles formed during bulk-phase endocytosis and transport final products of digestion into cytosol; digests worn-out organelles (autophagy), entire cells (autolysis), and extracellular materials.

45
Q

Describe the structure and function of Peroxisome

A

Vesicle contains several oxidases, enzymes that can oxidize (remove hydrogen atoms from) various organic substances. Oxidizes amino acids and fatty acids; detoxifies harmful substances, such as hydrogen peroxide and associated free radicals.

46
Q

Describe the structure and function of Proteasome

A

Tiny barrel-shaped structure. Continuous destruction of unneeded, damaged, or faulty proteins

47
Q

Describe the function of Mitochondria

A

Site of aerobic cellular respiration reactions that produce most of a cell’s ATP. Plays an important early role in apoptosis.

48
Q

What is Apoptosis?

A

Programmed cell death; a normal type of cell death that removes unneeded cells during embryological development, regulates the number of cells in tissues, and eliminates many potentially dangerous cells such as cancer cells.

49
Q

Describe the structure and function of the Nucleus.

A

Consists of a nuclear envelope with pores, nucleoli, and chromosomes. (mass of chromatin in interphase cells)
Nuclear pores control the movement of substances between the nucleus and cytoplasm, nucleoli produce ribosomes, and chromosomes consist of genes that control cellular structure and direct cellular functions.

50
Q

What is the process of each step during transcription?

A

Copying the information into a complementary sequence of codons. Three types of RNA are made from the DNA template:
1.Messenger RNA(mRNA) directs protein synthesis
2. Ribosomal RNA(rRNA) joins with ribosomal proteins to make ribosomes
3. Transfer RNA(tRNA) binds to amino acid and holds it in place during translation

51
Q

What is the process of Translation?

A

The nucleotide sequence in an mRNA molecule specifies the amino acid sequence of a protein. Ribosomes in the cytoplasm carry out translation. The small subunit of a ribosome has a binding site for mRNA; the larger subunit has three binding sites for tRNA molecules: a P site, A site, and E site.

The P (peptidyl) site binds the tRNA carrying the growing polypeptide chain. The A (aminoacyl) site binds the tRNA carrying the next amino acid to be added to the growing polypeptide. The E (exit) site binds tRNA just before it is released from the ribosome.

52
Q

The process of cell division in Interphase.

A
  1. Interphase begins.
  2. G0 phase- exit from the cell cycle (nondividing cell)
  3. G1 phase- Cell metabolically active; duplicates organelles and systolic components; centrosome replication begins.
  4. S phase- DNA Replicated.
  5. G2 phase- Cell growth continues; enzymes and other proteins are synthesized; centrosome replication completed
53
Q

The process of each step in Mitosis.

A

Prophase- chromatin condenses into chromosomes. The nuclear membrane disappears and centrosomes move to opposite poles.

Metaphase- centromeres of chromosomes line up at the metaphase plate.

Anaphase- centromeres of chromosomes split and move toward opposite poles of the cell.

Telophase- Mitotic spindle dissolves, chromosomes regain their chromatin appearance, new nuclear membrane forms.

Cytokinesis- Cleavage furrow forms and the cytoplasm of the parent cell fully splits.

After cytokinesis is complete, interphase begins.

54
Q

What are the three possible destinies of control of cell density?

A
  1. Remain alive and functioning without dividing.
  2. Grow and divide.
  3. Die
55
Q

The process of each step in Meiosis 1

A

Prophase 1- chromosomes shorten and thicken, the nuclear envelope and nucleoli disappear, and the mitotic spindle forms. Two sister chromatids of each pair of homologous chromosomes pair off, an event called synapsis, and form a structure called a tetrad. Parts of the chromatids of two homologous chromosomes may be exchanged with one another(crossing-over). Crossing-over results in genetic recombination, the formation of new combinations of genes.

Metaphase 1- tetrads formed by the homologous pairs of chromosomes line up along the metaphase plate of the cell, with homologous chromosomes side by side

Anaphase 1- members of each homologous pair of chromosomes separate as they are pulled to opposite poles of the cell by the microtubules attached to the centromeres. The paired chromatids, held by a centromere, remain together.

Telophase 1 and Cytokinesis- The net effect of meiosis I is that each resulting cell contains the haploid number of chromosomes because it contains only one member of each pair of the homologous chromosomes present in the starting cell.

56
Q

The process of Meiosis 2

A

Meiosis II, also consists of four phases: prophase II, metaphase II, anaphase II, and telophase II.

During meiosis II, each of the two haploid cells formed during meiosis I divide; the net result is four haploid gametes that are genetically different from the original diploid starting cell.

Anatomy & Physiology 1 Midterm (8 decks)

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