CH.4 BIOLOGY OF CELL Flashcards
1
Q
What is Cytology
A
Study of the Cell
2
Q
What is Histology?
A
Study of Tissue
3
Q
What is Microscopy?
A
The use of a microscope to view small-scale structures & is important to do Anatomic Investigations
4
Q
What are the Two Types of Microscopes used?
A
Light Microscope & Electron Microscope.
5
Q
What are the two types of Electron Microscopes & Describe them?
A
-Scanning Electron Microscope: Detailed 3D imaging, Electron beam moving across the surface
-Transmission Electron Microscope: 2D image, always us to see details of the specimen’s internal structure.
(Electron beam is direct)
6
Q
What are the Common Features seen in Cells?
A
Nucleus, Plasma Membrane, & Cytoplasm.
7
Q
What is the Plasma Membrane & What modifications can be seen on it?
A
Limiting barrier that separates the internal contents of the cell from the interstitial fluid
-Cilia, Microvili, & Flagella
8
Q
What is Interstitial Fluid?
A
Fluid found surrounding the cell
9
Q
What is the Nucleus and What it the Anatomical Structure of it?
A
-Contains DNA/ Largest Structure
-Nucleolus: Dark stained body of Nucleus
-Nucleoplasm: Fluid in the Nucleus
-Nuclear Envelope: Membrane around the Nucleus.
-Nuclear Pores: Open passageways formed by proteins that extend through fused regions of nuclear Envelope.
10
Q
What is the Cytoplasm
A
-Contains the Organelles and Nutrients between the Plasma Membrane & Nucleus.
11
Q
What are the Three Cytoplasmic Components?
A
1) Cytosol: Fluid, high water concentration, has dissolved macromolecules.
2) Inclusions: Clusters of a single molecule (Not organelle.
3) Organelles: Complex Structure that have unique functions & shapes.
12
Q
What are the Two Categories of Organelles?
A
1) Membrane-Bound Organelle: Enclosed by a membrane.
-Separates the contains inside the organelle from the cytosol.
2) Non-membrane bound Organelle: Free flowing, composed of protein & ribosomes.
13
Q
What are the Four General Cell Functions?
A
1) Maintain Integrity: (Support shape & function)
2) Dispose Waste
3) Divide (not all cells do)
4) Obtain Nutrients & make Chemical building blocks
- Metabolic reactions.
14
Q
What are the Chemical Structure of the Plasma Membrane?
A
1) Lipid Components
2) Membrane Proteins
15
Q
What are the Lipid Components of the Plasma Membrane
A
1) Phospholipid: Semipermable.
2) Cholesterol: Strengthens the membrane & stablizes it at extreme temp.
3) Glycolipids: Helps w/ cell to cell recognition.
16
Q
What are the two structural types of Plasma Membrane Protein?
A
-Integral & Peripheral.
17
Q
What is Integral Membrane Protein?
A
-Embedded in the Lipid Bilayer.
Phobic-phobic
-Many of these are glycoproteins
18
Q
What is Peripheral Membrane Protein?
A
- Internal or External of the Lipid Bilayer.
-Loosely attached & are often anchored to the exposed parts of the integral proteins.
19
Q
What are the 6 Specific roles that Membrane Proteins are categorized in? & What are their functions
A
1) Transport protein: Help Regulate substances movement across plasma membrane.
Ex: Channels, Carrier Protein, & Pump.
2) Cell Surface Receptor: Bind Specific Molecules (Ligands)
3) Identity Markers: Communicate to other cells that they belong to the body.
4) Enzymes: Either attached internal or external surface of cells to catalyze chem reactions.
5) Anchoring Sites: Secure Cytoskeleton to plasma membrane.
6) Cell-Adhesion Proteins: Cell to Cell attachment.
20
Q
What are Glycocalyx
A
- Coating of sugar at Cell’s external surface.
-helps with cell to cell recognition.
21
Q
What is the 4 Primary Functions of the Plasma Membrane?
A
- Serves as a physical Barrier
- Selectively Permeable Boundary
- Establishes & maintains Electrochemical gradients across the plasma membrane.
- Cell Communication.
22
Q
What is a Electrochemical Gradient?
A
Electrical charge difference across the plasma membrane.
23
Q
What are the Two Processes of Membrane Transport?
A
Active Transport: Needs energy, moves up the concentration gradient. (Or formation or loss of vesicle)
Passive Transport: Does not need energy, moves down gradient.
24
Q
What are the Two methods of Passive Process?
A
-Diffusion
-Osmosis
25
What is Diffusion?
- Random Movement of ions or molecules down their concentration gradient (high to low).
(Dependent on Concentration Gradient)
26
How does Diffusion reach Equilibrium?
- Substances are equally distributed.
27
What are the Two types of Diffusion?
-Simple & Facilitated Diffusion.
28
What is Simple Diffusion?
-Small & Nonpolar solutes
-Moves Molecules unassisted between phospholipid layer.
-Not regulated by plasma & dependent on gradient.
29
What is Facilitated Diffusion & What are the two types?
- Assists the Transport process for small charged or polar solutes.
- Channel-Mediated & Carrier Mediated Diffusion.
30
What is Channel-Mediated Diffusion?
-Facilitated Diffusion.
-Moves small ions (Na/K+) across membrane through water filled protein channels.
-Helps with Muscle & Nerve Cell function.
31
What are the two types of Transport Channels in Channel-Mediated Diffusion?
-Leak Channel: Always Open.
-Gated Channel: Usually closed, opens only in response to a stimulus for a sec.
32
What is the Carrier-Mediated Diffusion?
-Movement of Polar Molecules across Plasma membrane.
33
What type of Transport Channel in Carrier-Mediated Diffusion?
-Carrier protein in Plasma that binds to the polar molecule.
- Changes the protein shape & carries the polar molecule to other side of the plasma then releases.
34
What is a Uniporter? (Passive Processes)
Transport only one substance.
-Glucose Carriers
35
What is the Transport Maxinum? (Passive Processes)
- Max rate at which a substance can be transported. (Determined by # of channels & carriers in plasma membrane.
36
What is Osmosis?
- Passive Process
-Movement of H2O & does NOT involve movement of solutes.
-Low to high concentration gradient
37
What are Aquaporins? And how does it help with in the Plasma Membrane?
-Helps with Osmosis for water to pass in & out.
-Integral protein water channel .
38
What does it mean for the Plasma Membrane to be Selectively Permeable?
- Allows the passage of water but the phospholipid layer prevents the movement of most solutes (polar & charged).
39
What are the two ways Water crosses the Plasma Membrane?
-Aquaporins
- Slips between the molecules of the phospholipids (small & limited amounts).
40
What are the 2 classified categories of solutes based whether they can cross the membrane by the Phospholipid layer
a) Permeable Solutes: Small & non-polar solutes passes through. (CO2, O2, Urea)
b) Non-Permeable Solutes: Charged, Polar or large solute are prevented from crossing (Ions, glucose, & proteins)
41
Describe the Concentration Gradient Across the Plasma Membrane?
-Different from cytosol and Intercellular Fluid
-Greater concentration of solutes= lower concentration of H2O
42
What is Osmotic Pressure?
-Pressure exerted by H2O movement across the semipermeable membrane due to the change in water concentration.
- Will stop when it reached equilibrium.
43
What is Tonicity?
A solution's ability to change the volume or pressure of the cell by Osmosis.
44
What are the 3 terms used to describe the solute and solvent's concentration in a Solution?
-Hypotonic, Hypertonic, & Isotonic?
45
What is a Hypotonic Solution?
-Higher concentration of water in than solute.
Hemolysis will happen here.
46
What is Hemolysis?
-Erythrocytes Rupture when there is too much water in cell.
-Pure Water can cause this (bc it has no solutes)
47
What is a Hypertonic Solution?
-Higher concentration of Solute than water.
- Crenation happens here.
48
What is Crenation?
-Cell shrinking because of difference in concentration.
49
What is an Isotonic Solution?
-Equal H2O & solute inside and outside of cell.
-No net movement of H2O
50
What is Active Processes?
- Needs Cellular energy.
-Moves substances up concentration gradient.
51
What are the two types of Transports that take place in Active Processes?
-Active & Vesicular Transport
52
What is Active Transport?
- Movement of a solute (Ions or small molecules) against its concentration gradient. (low to high)
53
What are the two types of Active Transport?
Primary and Secondary Active Transport.
54
What is Primary Active Transport?
-Uses energy derived from ATP breakdown.
-Phosphorylation Happens.
55
Where are Ion pumps present in the Active Transport?
Primary Active Transport.
56
What is an example of Primary Active Transport?
-Sodium Potassium Pump
57
What is the Sodium Potassium Pump?
It is a specific type of Ion pump (Exchange pump): because it moves one ion in and another one out, against concentration gradient.
58
How much Sodium and Potassium go through the cell, & ATP?
3 Na+ out & 2K+ in, 1 ATP
59
Why is the inside of the cell negatively charged, especially when the Sodium/ Potassium pump is active?
- The negatively charged molecules are stuck inside because it can't pass through the cell.
60
What is Secondary Active Transport?
- Energy source from movement of another substance.
Ex: water flowing down a dam which moves the water wheel results in conducting electricity
61
What is an example of Secondary Active Transport?
-Water moving over a dam & a water wheel can generate electricity.
- Na+ gradient is often the source of potential energy, then converted to kinetic when Na+ moves into cell, down concentration.
62
Two type of Secondary Active Transport?
a) Symport
b) Antiport
63
What is Symport Secondary Active Transport?
-Two substances moved in the same direction by a Symporter.
- Ex: Glucose binds to Symporter in plasma membrane, the binding then alters the shape of the symporter, then both Na+ & Glucose is transported into the cell.
64
What is an Antiport Secondary Active Transport?
- Two substances moving in opposite directions by Antiporter.
- Na+ in cell, H+ moving out.
65
What is Vesicular Transport?
-Involves a Vesicle that transports large amounts/substances across the plasma membrane.
66
What are the two types of Vesicular Transport?
-Endocytosis & Exocytosis
67
What is Exocytosis?
Large substances/amounts are secreted outside the cell.
68
What are the steps of Exocytosis?
- Membrane of vesicle and plasma membrane come in contact, they rearrange so that the membranes fuse.
(Which requires to split ATP.)
69
What is Endocytosis?
-Large substance/ amount into the cell.
-Used to uptake nutrients, extracellular debris for digestion.
70
What are the steps of Endocytosis?
-Substances in the interstitual fluid is packaged into a vesicle that forms at the cell surface.
-Invagination happens= folding inward
-Pocket gets pinched off and forms a vesicle.
71
What are the three types of Endocytosis?
- Phagocytosis
-Pinocytosis
-Receptor-Mediated Endocytosis
72
What is Phagocytosis?
Cellular eating (only few types of cells are able to perform this.
-Forms pseudopodia
73
What is Pseudopodia?
Forms in Phagocytosis.
-Is a membrane extension that helps the cell engulf large external particles to the cell.
74
What happens once a particle is engulfed by the Pseudopodia in Phagocytes?
-Forms a newly formed vesicle fuses with a lysosome.
-Lysosomes will digest material that can't be indigested.
75
What are Lysosomes?
-Cellular organelle that contains digestive enzymes
76
What is a Pinocytosis? & when does it occur?
- Cellular Drinking, (Most cells perform this type).
- Occurs when multiple small regions of plasma membrane invaginate & several small vesicles as cell internalizes the interstitial fluid.
77
What is a Receptor-Mediated Endocytosis?
Uses receptors on the membrane to bind specific molecules within the interstitial fluid and bring then into the cells
78
What is the Process of Receptor Mediated Endocytosis?
- Ligand in the interstitial fluid bind to the Plasma Membrane receptors- forms Ligand-receptor Complex.
- The complex forms a Clathrin-coated pit by moving toward the regions.
-Pit invaginates, and the Clathrin coat is removed enzymatically. Which forms a intracellular destination.
79
What is a Membrane Potential?
Electrical charge difference at plasma membrane which represents the Potential Energy.
80
What is a Resting Membrane Potential?
- When the membrane potential is at rest.
-Muscle & Nerve muscle cells depend on this
81
What is Depolarization in Membrane Potential?
-Lots of Na+ rush in , makes inside more positive
82
What is Hyperpolarization in Membrane Potential?
Lots of K+ move out (Negative inside).
83
What are the two cellular conditions that are significant in Establishing & Maintaining an RMP?
1) Cells has unequal distribution of ions & charged molecules across plasma membrane. (K+ more inside while Na+ outside)
2) Relative Amounts of positive & negative charges are not equally distributed at Plasma.
84
What is ElectroChemical Gradient?
At the top of the slide, there are a bunch of kids (positive ions, like sodium).
At the bottom of the slide, there are fewer kids.
Kids naturally want to slide down because there’s more space below—this is like the chemical gradient (moving from high to low concentration).
Now, imagine there’s a magnet at the bottom of the slide pulling the kids down even more. This is like the electrical gradient, where opposite charges attract.
Together, the slide and magnet make the kids move down faster—just like the electrochemical gradient helps ions move across a cell’s membrane, creating the membrane potential! 🚀
85
Direct Contact between cells are important.
86
What is Ligand-Receptor Signaling?
-Most communication between cells occur her.
- Cells that recieve the info has a receptor that binds w/ the ligand. Then creates a cellular reaction
87
What the Three General types of Receptors that Bind Ligands?
1) Channel-linked Receptors.
2) Enzymatic Receptor
3) G-protein Coupled Receptors.
88
What is Channel-linked Receptors? (Ligand)
- (Chemically gated Channels)
-Permit ion passage either in or out of a cell in response to ligand binding.
-It is required to initiate electrical changes to RMP in skeletal/ cardiac muscle cell& Nerve cells.
89
What are Enzymatic Receptors?
-Type of Receptor that binds ligands.
-Functions as protein kinase enzyme & are activated to directly phosphorylate other enzymes in cell.
90
What are G protein-coupled Receptors?
Involved protein kinase activation but activated indirectly through the G protein that serves as a intermediate molecule
91
What are the five Membrane-Bound Organelles?
-Golgi Apparatus, Endoplasmic Reticulum, Lysosomes, Peroxisomes, & Mitochondria.
92
What is Endoplasmic Reticulum?
-Extensive, interconnected membrane network that varies in shape in one continuous lumen.
- Serves as a point of attachment of both ribosomes.
93
What is Rough Endoplasmic Reticulum?
- Where Ribosomes are attached.
94
What are Ribosomes in Rough ER?
-Produce protein in the Rough ER, that is released from the plasma & serve as a digestive enzyme in Lysosome.
95
Where do the Proteins go after being made from the Rough ER?
-Through Vesicles to Golgi Apparatus.
96
What is Smooth ER?
-Carries diverse metabolic processes that vary by cell type.
- Produces lipids, Synthesis, transport, & storage.
97
What is the Golgi Apparatus?
-Composed of several elongated, flattened, membranous sacs.
-Functions: Modify, package, & sort package that were made by the Rough ER.
98
What are the two poles in Golgi Apparatus?
a) Cis-faces= Closer in proximity to the ER & diameter of its flattened sac is larger compared to trans-face.
b) Trans-face= Distal from ER.
99
What do Secretory Vesicles carry?
- They form & carry both the modified & newly formed molecules
100
What is Autolysis?
Cell digest itself when damaged or dies
101
How does Lysosomal Storage Dieases happen?
-Happens when there is an accumulation of incompletely digested molecules in Lysosomes & mutation in Lysosome enzyme genes.
102
What is Peroxisomes? & how are they formed?
-Small membrane-enclosed, spherical sacs that contain 50 diff enzymes.
- Function: Detoxifies substances that are dangerous to the cell.
-Engages in Metabolic Functions.
-Formed by vesicles punched off from Rough ER.
103
What is the Endo-membrane System?
-Extensive array of membrane-bound structures.
-All structures are either attached together or connect through vesicles that move between them.
104
What is the Mitochondria?
-Oblong-shaped organelles that have double membrane w/ folds of inner membrane.
-Produces ATP
105
What are the Non-membrane bound organelles?
-Composed of either protein alone or w. ribonucleic Acid.
- Includes ribosomes, centrosomes, Proteasomes, & Cytoskeleton
106
What are Ribosomes?
-Contain RNA & protein that are arranged in large & small subunit.
Large Subunit contains hollow areas A,P, & E sites
107
What are the two types of Ribosomes?
1) Bound Ribosomes: Attached to external surface of ER membrane to form Rough ER.
- Synthesizes protein
2) Free Ribosomes: Suspended within Cytosol.
-Synthesizes all other proteins.
108
What are Centrosomes?
-Close to the Nucleus
-Contains a pair of centrioles.
-Function: Organizing the microtubules in the Cytoskeleton & cellular division.
109
What are Proteasomes?
-Major protein digesting organelles located in both Cytosol & Nucleus.
-Degrade cell proteins through ATP dependent pathway & controls the quality of exported cell proteins.
110
What is Ubiquitin?
A protein bounded to a targeted protein removal, to mark for destruction to Proteasomes.
111
What are Cytoskeleton?
- Framework of diverse protein that extends both beneath the plasma & through interior of cell.
- Function: Supports the cell & organize the organelles.
112
What are the three types of protein molecules that form Cytoskeleton?
1) Microfilament
2) Microtubules
3) Intermediate Filaments.
113
What is a Microfilament?
Smallest component of Cytoskeleton
-Composed of globular Actin protein monomers in two twisted filaments.
- Functions: Maintain Cell shape, internal support (Plasma membrane) & cell division.
114
What are Microtubules?
-Largest Component of cytoskeleton.
- Composed of globular tubulin protein monomers, organized into hollow cylinders.
-Functions: Maintains shape, cell transport, cell division.
115
What are Intermediate Filaments?
-Intermediate size w/ Microfilaments & Tubules.
-Less flexible & extends across inside of cell.
- Functions: Rigid roots to both support the cell & stabilize between them.
116
What are the 3 structures of Cell's External Surface?
-Cilia & Flagella: Extensions of plasma membrane, involving movement .
- Microvilli- Structures that increase the surface area of the plasma membrane.
117
What is Cilia?
Small, hairlike projections extending from exposed surfaces of some cells.
-Function: Moves mucus & other substances on cell surface toward throat then expelled from respiratory system.
- Contain supportive microtubule protein & enclosed by plasma membrane.
118
What is Flagella?
-Longer & wider than Cilia, only one present.
-Function: Propel on entire cell.
119
What is Microvilli?
-Thin, microscopic membrane extensions of plasma membrane.
- Lack powered movement.
120
What are Membrane Junctions?
-Composed of integral & peripheral membrane protein.
-Function: Connect & support cells.
121
What are the Three type Membrane Junctions?
-Tight Junction, Desmosomes, Hemidesmosomes.
Gap Junction.
122
What are Tight Junctions?
-Form strands or rows of proteins.
- Prevent substance from unregulated passing between epithelial cell.
-Maintains Polarity of Epithelia.
123
What are Desmosomes Junctions?
-Adhering spots
-Composed of several different proteins that bind neighboring cells.
-Contains Protein Plaque
has Hemidesmosomes
124
What are Protein Plaque?
Thickened structure located on internal surface of plasma membrane of adjoining cells.
125
What are Hemidesmosomes?
- A type of desmosomes
- (half of a desmosomes)
-Anchor the basal surface of cells of the epidermis to the underlying basement membrane.
126
What is Gap Junctions?
-Provide a direct passageway for substances to move between neighboring cells.
- Composed of six integral plasma membrane protein Connexons.
127
What are Phosphodiester Bonds?
Links Nucleotide monomers through Phosphate groups to form a polymer strand. (Sugar & Phosphate group bind)
128
How many DNA does Somatic cells have?
46 double stranded DNA
129
What are Histones & what does it form?
-A cluster of special nuclear proteins where DNA's double helix winds around to help package DNA molecules in Nucleus
- Forms the complex Nucleosomes.
130
What are Chromatin?
-A form of finely filamented mass that DNA & its protein take shape. (Histone & DNA)
- when Cell does not divide
131
What are Chromosomes?
Chromatin becomes tightly coiled masses (only when cell dividing)
132
What are Genes?
A segment of nucleotides in DNA that provide specific instructions for synthesis of specific proteins.
133
What is a Promoter Region & a Terminal Region?
- Start signal
-Stop signal for transcription.
-in DNA
134
What is Transcription & What are the structures included in it?
- Synthesizing of RNA.
- Nucleus, Ribonucleotides (Monomer used to synthesis RNA) , RNA polymerase
135
What is Translation & What are the structures included in it?
- Synthesizing of Protein
- Cytoplasm by ribosomes, mRNA, tRNA, AA, Protien.
136
What are the three types of RNA?
mRNA, tRNA, & rRNA (Serves at Catalysts during AA assembly into protein.
137
What are the three steps of Transcription?
1) Initiation: RNA attaches to DNA Temple strand & copies the nucleotides.
2) Elongation: Hydrogen bonds form between base of the RNA & the complementary bases of DNA strand. (Phosphodiester bond formed).
3) Termination: Hydrogen bonds broken between the DNA strand & the new mRNA strand.
138
What does mRNA need to do before it leaves the Nucleus?
1) Needs to be Spliced of its Introns, Exons are spliced together.
2) Capping of the end of the mRNa that contains Guanine.
3) Poly A tail: removes terminal segments and places a tail at the other end.
139
How is Poly A tail help with the measurement of mRNA age?
Over time, Nucleotides are removed and the tail is shortened.. Then when a certain amount of the Poly A tail remains, Nucleus enzyme destroys the mRNA.
140
How does the mature mRNA leave the nucleus after modified?
Through the Nuclear pores to enter cytosol then to the ribosomes.
141
Where is the location of Translation?
In the ribosomes at the Cytosol.
142
What are the Large Subunits that Translation needs in Ribosomes?
1) A (Aminoacyl) Site: New AA Form.(Checking in doctor’s office)
2) P (Peptidyl) Site: holds newly forming polypeptide. (In room waiting for doctor to be seen)
3) E (Exit) Site: tRNA that is exiting the ribosome. (Finished)
143
What is a Codon?
A set of 3 Nucleotides
144
What is a Start Codon?
-Start point of mRNA strand to begin synthesizing protein.
- AUG (Methionine)
145
What is a Stop Codon?
-Stop point of reading mRNA.
- UAA, UAG, UGA.
146
What does tRNA do?
Serves as an adapter to bring a Specific AA to a specific mRNA Codon.
147
What is the Anatomy of an tRNA?
Amino Acid Acceptor
-Anticodon: Three nucleotides in tRNA. (This determines the specific AA to which tRNA attaches to.
148
What is an Aminoacyl -tRNA Synthetase?
-Specific enzyme that catalyzes the process of tRNA binding to its designated AA.
149
What is Interphase? What are the three phases that happens in Interphase?
-Cell prepares for Cell Division.
-G1, S1, G2
150
What happens during G1 phase?
Cells grow & produce new organelles & others needed for DNA replication.
-Replication of centrioles to produce two pairs happens here.
151
What happens during S phase
DNA strands are replicated & form Sister Chromatids
152
What are Sister Chromatids?
Replicated DNA strands, remains attached with Centromeres.
153
What happens during G2 phase?
Centriole replication is complete & enzymes/ other structures are synthesizes (making it ready for Mitosis.
154
What are the five stages in Mitosis?
-Prophase
-Metaphase
-Anaphase
-Telophase
-Cytokinesis.
155
What happens in Prophase?
-Chromatin becomes visible & supercoil into chromosomes.
-Nucleolus breaks down & disappears.
-Spindle fibers grow & push the Centriole pair.
156
What happens in Metaphase?
-Chromosomes line up as the spindle fibers line them up to the midline.
157
What happens in Anaphase?
Sister Chromatids are pulled apart
158
What happens in Telophase?
(reverse Prophase):
Chromosomes uncoil, Nucleus forms Nucleolus. Mitotic Spindles break up & disappear.
Nuclear envelope forms.
159
What happens in Cytokinesis?
Cell separates into two (Cleavage furrow)
-May overlap w/ Anaphase & Telophase.
160
What happens when reduced metabolic function in Normal cells?
-Reduced ability to maintain homeostasis.
-Alters structure or shape of cell & organelles, or chromatin & chromosomes.
161
What two mechanisms in which cells die?
- Killed by harmful agents or mechanial damage.
- Apoptosis (Initiated by Ligand-receptor signaling.
162
163
What do the Transport Vesicles do for the E.R.
Transports the proteins to the Golgi apparatus
