Term
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Definition
| Plasma membrane. It is a double membrane lipid bilayer that forms a barrier for the cell. It consists of polar heads and nonpolar tails. The E-face is on the outside of the bilayer and the P-face is on the inside. The P-face has more integral proteins. |
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Term
What is this structure and its main function?
[image] |
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Definition
Clathrin-coated pits. They are involved in receptor-mediated endocytosis. When cargoporteins accumulate and bind to cargo receptors, they recruit adaptin and clathrin which form basket-like cages that coat the vesicles during endocytosis. |
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Term
| What are the differences in structure and function between rER and sER?[image] |
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Definition
rER is continuous wiht the nuclear envolope and it is predominant in secretory cells. It is involved with protein synthesis
sER is predominant in hepatocytes where lipid metabolism and detoxification occur. It is also involved in steroid synthesis. It does not have ribosomes. |
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Term
| What is this structure and its main function?[image] |
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Definition
| Golgi apparatus. It is responsible for post-translational modification, sorting, and packaging of the newly synthesized protein. The cis face is closest to the ER and the trans face is closest to the plasma membrane. |
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Term
| [image]What is this structure and its main function? |
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Definition
| Mitochondria. This is the powerhouse of the cell. It generates ATP via oxidative phosphorylation and TCA. It is derived from prokaryotic cells and it can determine the fate of cells by inducing apoptosis. Not present in RBCs or keratinocytes. |
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Term
| [image]What is this structure and its main function? |
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Definition
Actin.
- anchorage and movement
- microvilli for absorption of nutrients and water
- locomotion
- extension of cell processes
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Term
| What is this structure and its main function?[image] |
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Definition
Microtubules: transportation
- Involved with transportation within the cell. This includes vesicular transport and movement of cilia and flagella
- They extend from the microtubule organizing center (MTOC) which is in close association with the nucleus. They extend out of the MTOC from gamma-tubulin rings.
- The (-) end is the nongrowing end and the (+) end extends outward
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Term
| What is this structure and its main function?[image] |
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Definition
Intermediate filaments: mechanical strength
- Intermediate filaments have more of a structural role and they do not continuously reform.
- They play a role in cell-cell and cell-matrix junctions
- Classes include keratins, vimentin, neurofilaments, lamins
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Term
What is this structure and its main function?
[image] |
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Definition
Mallory bodies are an accumulation of intermediate filaments in the liver. |
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Term
| [image]What is this structure and its main function? |
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Definition
| Centrioles. Thse are the central point of MTOC and consist of 9 sets of triplets. They have a short drum-like appearance. Centrosome refers to 2 centrioles paired at 90 degrees from each other. |
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Term
What is this structure and its main function? (the black stained areas)
[image] |
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Definition
| Inclusions. These are non-moving, non-living structures. They are the products of metabolic activity. They consist of pigment granules, lipid droplets, and glycogen. |
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Term
Identify the different parts of this structure and their main functions
[image] |
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Definition
- Nuclear envelope forms the barrier of the nucleus with an inner and outer membrane (bilayer).
- Nuclear lamina is the scaffolding for the chromosomes and the nuclear pores and composed of intermediate filaments
- Nuclear pore transports ribosomes out of the cell and organelles into the cell for DNA synthesis
- Chromatin: heterochromatin (dark stain, transcriptionally inactive) and euchromatin (light stain, transcriptionally active)
- Nucleolus is involved with rRNA synthesis and ribosome assembly
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Term
| Distinguish between the structures of heterochromatin and euchromatin and identify how they differ |
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Definition
Heterochromatin is tightly packed and appears as a dark stain within the nucleus. It is transcriptionally inactive.
Euchromatin is loosely packed and appears as a light stain within the nucleus. It is transcriptionally active. |
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Term
| What is this structure and its main function?[image] |
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Definition
| Nuclear lamina. This is a meshwork composed of intermediate filaments. It is the scaffolding for the chromosomes and nuclear pores. |
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Term
What is this structure and its main function?
[image] |
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Definition
| Barr body. In individuals with 2 X chromosomes, 1 X chromosome can be repressed and it is tightly coiled into a Barr body. It is commonly seen adjacent to the nuclear envelope. It indicates that an individual has an X chromosome, but it does not indicate sex. |
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Term
What is this structure and its main function?
[image] |
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Definition
| Apoptotic bodies. These are condensation of nuclear materials that indicate programmed cell death. |
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Term
| What are the functions of integral membrane proteins? Give examples of each |
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Definition
Integral membrane proteins span the membrane. They function in cell metabolism, regulation, and integration.
Integral proteins can include pumps, channels, receptors, linkers, enzymes, or structural proteins.
Carrier proteins - have receptors that binds ligands
Channel proteins - ion selective |
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Term
Compare and contrast pinocytosis, endocytosis, and exocytosis |
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Definition
Endocytosis - brings substances into cells (includes pinocytosis, phagocytosis, and receptor-mediated endocytosis)
Exocytosis - releases substances out of cells, constitutive, and regulated
Pinocytosis - cell drinking, nonspecific, absorb small proteins and fluid
-all cells use pinocytosis to monitor the external environment |
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Term
| What is the function of lysosomes? |
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Definition
Lysosomes are digestive organelles that digest cellular debris with a low intracellular pH of 4.7. They contain tough membranes that resist digestion. Autophagy refers to self-eating within the cell. |
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Term
| List the components of the cytoskeleton and give examples of their functions and related pathologies |
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Definition
- Microtubules - transportation
- Actin - motility
- Intermediate filaments - mechanical strength
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Term
| Describe the packaging of DNA in the nucleus |
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Definition
The nuclear lamina is the scaffolding for the chromosomes and the nuclear pores. Chromatin is packaged to fit in the nucleu. Heterochromatin is tightly packed and euchromatin is transcriptionally active.
dsDNA is wrapped around histones. Bundles of histones with DNA form chromosomes. |
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Term
| Define what telomeres are and describe how they are linked to oncogenesis |
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Definition
| Telomeres are the ends of chromosomes. They shorten with each cell division, so the telomerase enzyme repeatedly adds nucleotide sequences to the telomere ends to maintain the length of the chromosome. Malignant tumors have abundant amoutns of telomerase. |
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Term
| Describe the Barr body and how it is used in genetic testing. |
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Definition
| Barr bodies are used to detect the presence of an X chromosome. If it is present, it indicates that an individual has an X chromosome, but it does not indicate the sex of of the individual. |
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Term
| Explain the cell cycle and how it is regulated |
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Definition
- M-phase: mitosis
- Interphase:
- G1- gap1 protein synthesis,
- S - DNA synthesis,
- G2 - gap2 growth and reorganization,
- G0 - stablise cells,
- GTD phase: static cells
The cell cycle is regulated by a two protein complex: cyclin and cyclin dependent kinase (CDK). There are checkpoint regulators that serve as different complexes during different stages of the cell cycle. |
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Term
| Define mitotic catastrophe |
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Definition
This is when the DNA-damage checkpoints malfunction or when the spindle assembly checkpoint in mitosis malfunctions.
Failure to arrest the cell cycle before or at mitosis results in abberrant chromosome segregation such as aneuploidy
Malfunction at G1 restricton checkpoint may result in malignant transformation |
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Term
| Briefly describe mitosis and meiosis |
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Definition
Mitosis:
- cell division
- follows S phase of cell cycle
- cell goes from 4N after S phase to 2N after division
Meiosis:
- gametes
- reductional division to 1N
- 2 mitotic divisions
- males: 4 spermatids
- females: 1 oocyte and 3 polar bodies
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Term
| Compare and contrast necrosis and apoptosis |
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Definition
- Necrosis - accidental death due to trauma. cell will lyse and explode
- Apoptosis - programmed cell death. phagocytosis clears up debris
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Term
| What are the characteristics of epithelial cells? |
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Definition
- Organized - either consist of covering (skin) or glands
- Cohesion - held together with cell to cell connections
- Shape - nucleus will mimic overall shape. epithelial cells contain apical and basal portions of the cell.
- Avascular - has no blood vessels
- Cytokeratins - intermediate filaments found in epithelium that serve as great biomarkers of epithelial derivatives
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Term
| What are the components of the basement membrane? |
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Definition
- Basal lamina - lamina densa and lamina lucida
- Reticular lamina - connective tissue and reticular fibers that help form the basement membrane
The basement membrane is important because it helps anchor the cells. It also forms a strong barrier. |
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Term
| How do epithelial cells demonstrate polarity? |
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Definition
Epithelial cells contain an apial surface and a basal surface.
Apical surface - adjacent to the lumen
-Apical surface will have more microvilli, receptors, and secretory vesicles.
Basal surface - adjacent to the basal lamina
-Basal surface contains golgi and ER
The phospholipid compositions of apical and basal surfaces also differ
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Term
| What are the functions of epithelium? |
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Definition
- Protection - protects from water loss and infection, especially multilayer cells
- Absorption - i.e. microvilli on intestine is important for nutrient absorption
- Secretion - mucous glands are important for secretion
- Transportation - cilia will move in respiratory tract
- Contractility (myoepithelium) - cells have contractile proteins
- Sensation (neuroepithelium) - smell and taste
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Term
| What are the 3 functional types of intercellular junctions? |
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Definition
- Adhering juctions: zonula adherens, desmosome, hemidesmosomes
- Impermeable junction: zona occludens
- Communicating junctions: gap junctions
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Term
What kind of junction is this and how does it function?
[image] |
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Definition
| Zona Occludens. This is a tight junction. It functions as a belt that goes all the way around the cell. Adjacent cell membranes are fused. Its main function is to prevent the movement of materials between adjacent cells. This is really important in the blood-brain barrier. Epithelium lines blood tissue and keeps blood from interacting with nervous tissue |
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Term
What kind of junction is indicated by the filaments and how does it function?
[image] |
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Definition
Zonula adherens. Actin filaments insert into plaques. They serve as cell adhesion molecules (CAMs). Their function is to contribute to adhesion.
In metastasis, this breaks down. Highly metastatic cancdrs downregulate cell adhesion molecules |
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Term
What is this structure and how does it function?
[image] |
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Definition
| Desmosome (macular adherens). This is an attachment plaque with intermediate cytokeratin filaments. It is from the cadherin family and it functions as tight adhesion between cells. |
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Term
| What is this structure and how does it function?[image] |
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Definition
| Hemidesmosome. This is located in basement membrane/basal lamina. It is an attachment plaque made of intermediate cytokeratin filaments. It is from the integrins family and its function is tight adhesion to basal lamina. |
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Term
| What is this structure and how does it function?[image] |
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Definition
| Gap junction. These are also known as connexins. They generate a central pore with a barrel-like structure in whic ions and small molecules can pass through. This type of junction is very prevalent in heart muscle to control electrical impulse and communication. |
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Term
1) What kind of cells are these? 2) Where is it found? 3) What is the function associated with it?
[image] |
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Definition
| Simple squamous. It lines blood vessels, alveoli of the lungs, and serous membranes. The nucleus is flat. |
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Term
| 1) What kind of cells are these? 2) Where is it found? 3) What is the function associated with it?[image] |
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Definition
| Simple cuboidal. One layer of cube cells. Found in kidney - collecting ducts, proximal, distal, loop of Henle |
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Term
1) What kind of cells are these? 2) Where is it found? 3) What is the function associated with it?
[image] |
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Definition
| Simple columnar. It is found in the intestine. It's main responsibility is absorption. |
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Term
Microvilli – apical finger-like protection to increase surface area
-actin – cortical webs of actin support microvilli
-glycocalyx – sugar protein mixture that forms top area
-brush border – composition of microvilli |
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Definition
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Term
1) What kind of cells are these? 2) Where is it found? 3) What is the function associated with it?
[image] |
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Definition
| Microvilli. These are apical finger-like projections to increase surface area. It includes actin for support, glycocalyx, and exists as a brush border. |
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