exam 1 Flashcards
Capable of dividing and renewing themselves for long periods
• Unspecialized
• Generate daughter cells that can differentiate into many specialized cells
• Exist in embryos & adult tissues
stem cells
Potential of a single cell to develop into an entire organism
totipotent
• Ability to develop into all cell types of the body, but not supporting structures (placenta, amnion, etc.)
pluripotent
Ability to give rise to a small number of different cell types
multioitent
• Capacity to give rise to a single cell type
Unipotent
Found in early embryos
Able to differentiate into MANY cell types = plasticity
pluripotent stem cell
Blood cells: red blood cells, B lymphocytes, T lymphocytes, natural killer cells, neutrophils, basophils, eosinophils, monocytes, macrophages, platelets
hematopathic stem cells
Epidermis, keratinocytes, hair follicles
skin stem cells
Neurons, astrocytes, oligodendrocytes
neural stem cells
Digestive tract lining: absorptive cells, goblet cells, Paneth cells, enteroendocrine cells
epithelial stem cells
- Originally found in bone marrow
- Also located in adipose tissue, nervous system, skin, tendon, ligaments, synovial membranes, muscle, trabecular bone
- Give rise to osteoblasts, chondrocytes, adipocytes & other connective tissue
Multipotent Stem Cells (Adult)
Able to differentiate into 1 type of cell
Ex. Hepatoblasts can differentiate to hepatocytes of
the liver
unipotent
intermediate cells
Progenitors
Daughter cells from same replication have different fates
asymmetric cell division
dysregulation of ________ cell division lead to cancer
asymmetric
Microenvironment that controls stem cell self-renewal Prevents stem cells from becoming depleted or
overproduced
Controlled by extrinsic & intrinsic signaling
Including nutrients and growth factors in the fluid surrounding the cell
stem cell niche
Use of stem cells to treat the following conditions
Parkinson’s disease, Type 1 diabetes, Alzheimer’s disease, stroke, spinal cord injury, burns, heart disease, osteoarthritis, rheumatoid arthritis
• What are proteoglycans made of?
GAG’s (mucopolysaccharides) and proteins
negative charged sugars
Also called mucopolysaccharides
Chondroitin sulfate, keratan sulfate, heparan sulfate
GAG’s (mucopolysaccharides)
• What impact does the negative structure of GAGs have on its function?
because of its negative structure of GAG’s water floods into the matrix containing GAG’s and creates a swelling pressure
What is the difference between a proteoglycan monomer and aggregate?
Monomers give bottle brush appearance
GAGs repel each other
Aggregate is many monomers attached to hyaluronic acid
Aggregate attached to cell surface
Where are proteoglycans located in the body?
They are found in all connective tissues, extracellular matrix (ECM) and on the surfaces of many cell types.
How is collagen assembled (in general)?
three helical polypeptide a chains of amino acids that wind around one another forming a collagen triple helix
How would collagen be organized in bone vs tendons?
collagen provides strengh and support for bones and tendons
How does elastin differ from collagen?
rubber like connective tissiue it is able to stretch and relax without tearing, found in lungs, large arteries and skin,
Genetic mutations in collagen or elastin will lead to which diseases?
scurvy vitamin c (deficiency), osteogenesis imperfecta (brittle bone disease), ehlers- danlos syndrome (stretchy skin), marfan syndrome, antitrypsin deficiency (inappropriate destruction of lungs)
What is the main adhesive protein in connective tissue?
Fibronectin
What it the main adhesive protein in epithelial tissue?
Laminin
Which cell junction and proteins seals epithelial cells together?
Tight Junction,
cadherin
Which cell junction and proteins are involved with anchoring to the basement membrane?
Hemidesmosomes
Which cell junction protein joins cells by binding actin bundles?
adherens
What are desmosomes?
anchor intermediate filaments between cells
what do integrins bind to for cell-cell or cell-ECM interactions?
Ligands
How are adhesion molecules related to cancer, leukocyte deficiency and pemphigoid?
when normal cell to cell and/or cell to matrix interactions are altered or interrupted, disease processes can be triggered.
Which molecules are overexpressed during asthma and rheumatoid arthritis?
asthma ICAM-1 (iimunoglobin superfamily),
Rheumatoid arthritis integrin LFA-1 & ICAM-2
What does selectin do?
bind carbohydrates
How are cell adhesion molecules involved in the 4 steps of extravasation?
when a leukocyte from the immune system responds to an infectious agent in tissue, its adhesion molecules must encounter their their ligands and facilitate that cell’s movement from blood into tissiue
What types of lipids are found in the cell membrane?
pfospholipids, cholesterol, and glycolipids
Why is the structure of a phospholipid important for membrane functionality?
make up 40-80% of the entire membrane, and it provides structure and regulation
What types of movements may phospholipids encounter?
lateral movment, rotation, and flexion
What are some examples of phospholipids with a glycerol backbone?
shingophospholipids, glycerolphospholipids
What is the backbone of sphingomyelin?
glycerol
How do fatty acid tails of membrane lipids (saturated or desaturated) impact membrane fluidity?
saturated has low levels membrane fluidity. and in unsaturated membrane fluidity increases
What is the difference between the inner and outer leaflet of the membrane?
the inner leaflet is closer to the cytosol than the outer leaflet
Do cholesterol-rich regions of the membrane have more or less movement?
less movement
How does cholesterol impact cell membrane function?
Cholesterol decreases motion of the phospholipids = increased rigidity & strength of the membrane
What are the functions of lipid rafts?
cholesterol transport, endocytosis, and signal transduction
What are glycolipids made of?
lipids and sugars
Which leaflet is the glycocalyx attached?
outer leaflet
What is the difference between transmembrane and lipid-anchored proteins?
transmembrane is Embedded in the lipid bilayer from cytosol to exterior adn lipid anchored proteins are bonded to a lipid, but does not extend through bilayer
Where are peripheral proteins found?
found on sytosolic side
What are some functions of membrane-bound proteins?
- enable ions to enter/exit cell
- enable other molecules to enter/exit cell
- enable response fromhormone or other compund
- bind GTP for cell signaling in response to hormone.
How are G-actin and F-actin different?
- G-actin – Globular (single subunit)
* F-actin – Filamentous (2 long strands wound together)
Which end is G-actin added to in F-actin?
+ end = where G-actin is added
What are the steps in synthesis of F-actin?
LAG, POLYMERIAZATION, STEADY STATE
What are the functions of actin microfilaments?
Regulation of the physical state of the cytosol
How does actin impact cytosol fluidity?
Cytosol can be:
• Gel – firmer due to longer F-actin strands that are bundled or cross-linked
• Sol (soluble) – more liquid due to depolymerization of F-actin
What are the functions of contraction in a non-muscle cell?
- necessary for cell movement
- work on concert with myosin
- contraction helps support function
- important closing gap of cells in healing wounds
- necessary for cell division
How many tetramers make up an intermediate filament?
8 tetrameres
Which form of energy is required for synthesis of microtubules?
GTP
what are the functions of microtubules? (such as flagella, etc)
transportation of chromosomes during division
What is the structure of a microtubule like?
the structure resembles a hollow cylindrical tube
How is a microtubule disassembled?
-Occurs when dimer addition slows & GTP cap is lost -Loss of the GTP cap prevents new dimers from binding -Also causes instability (peeling of protofilaments)
drugs that impact cytoskeletal function
- taxol binds and stabilizes microtubles
- colchicine, colcemid binds tubuliin and prevents their polymerization
- vinblastine, vincristine binds tubulin dimers and prevents their polymerization
What is the function of each of the 5 parts of the nucleus?
-Nuclear envelope = phospholipid bilayer membrane
-Nuclear pores =
communication between nucleus & cytosol
-Nucleoplasm = fluid inside nucleus
-Nuclear lamina = structural organization by intermediate filaments
-Nucleolus = suborganelle where ribosomes are made
Where and with what does protein synthesis occur?
rough endoplasmic reticulum (RER), and RER are incorporated into organelle membrane
What is synthesized in the smooth ER?
lipid and steroid hormones
What is the function of the rough ER?
protein synthesis
Where is calcium stored in the cell?
rough endoplasmic reticulum
Where is ATP generated in the cell?
cytoplasm
What is the digestive system of the cell?
lysosome
Mitochondria! structure and function.
- 2 lipid bilayer membranes: inner & outer
- Produces 90% of energy for cell
What is the structure and function of the golgi apparatus?
- Made of stacks of flattened membranous sacks
- Makes proteins from RER more specific & sorts them
How do prokaryotes & eukaryotes differ?
- prokaryotes lack nucleus, circular dna
- eukaryotes have a nucleus and are larger than prokaryotes
What are the 2 types of glycocalyx on bacteria?
capsule, and slime layer
What are the parts of a flagellum?
filament, hook, and basal body
What are fimbriae & sex pili important for?
they are responsible for movement
What makes up the bacterial cell wall?
peptidoglycan
How are Gram (+) and Gram (-) bacteria different?
- gram (+), crystal violet color, thick (multilayer) has no periplasmic space or outer membrane, has vurtually no Lipopolysacchiride
- gram (-) pink or red color, thin single layer, has outer membrane and and periplasmic membrane, high lipopolysacchiride content
Where does oxidative phosphorylation occur in bacteria?
cytoplasm
How are plasmids important to bacteria
Virtually all plasmids that are used to deliver DNA contain genes for antibiotic resistance.
What type of ribosome is found in bacteria?
Prokaryotic ribosomes are 70s, Composed of 2 subunits (30S and 50S)
What is an endospore?
Unique structures produced by some
bacteria that are a defensive strategy
Importance of gut microbiota
Obesity
Diabetes
Allergies
Behavior
How can we influence our microbiome?
Prebiotics
Probiotics
What are important characteristics of viruses?
Contain single type of nucleic acid-DNA or RNA
Protein coat surrounds nucleic acid – capsid
May contain an envelope
Use host “machinery”
What are some challenges to people with viral infections
What is a capsid?
Protein coat (capsid) surrounding a nucleic acid core
What makes up an enveloped virion?
phospholipids
What are the steps in viral replication?
- Attachment of the virion to the host cell
- Entry of the virion or its genome into host cell
- Synthesis of new nucleic acids and viral proteins by the host cell’s enzymes and ribosomes
- Assembly of the new virions within the host cell
- Release of the new virions from the host cell
What are prions and how do they work?
Infectious proteinaceous particles
Transmissible spongiform encephalopathies
Scrapie
Mad cow (BSE) and vCJD (Creutsfeldt-Jakob disease) Kuru
Chronic wasting disease
