which one is acid fast bacteria how it looks color and shape after staining acid fast stain are used to differentiate acid fast organism such mycobactria
In: Biology
discuss why nutrition and weight status are important for health
In: Biology
Please fill out the definition of each term
11. Antibody
12. Antibody isotype (class)
13. Antibody isotype (class) switching -- class switch recombination
14. Antigen (Ag)
15. B cell receptor (BCR)
16. CD4
17. CD8
18. Cell-mediated immunity
19. Chemokine
20. Chemotaxis
21. Cluster of differentiation (CD)
22. Commensal organism
23. Complement (C')
24. Complementarity determining regions (CDRs)
25. Co-receptor
26. Cytokine
27. DAMP
28. Dendritic cell
29. Effector cell
30. Effector molecule
In: Biology
Which of the following enzymes could be used to excise most of the gene for subunit 1 of cytochrome c oxidase without fragmenting any of the other genes? [Hint: use the 2 cutters display option.]
BstEII
SgrAI
BglI
AclI
In: Biology
Cystic fibrosis (CF) is a genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. CF is inherited in an autosomal recessive manner with simple Mendelian inheritance. It is caused by the presence of mutations in the gene for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. A normal couple intends to have children but consult a genetic counselor because the man has a sister with CF and the woman has a brother with CF. There are no other known cases in their family. They want to know: (1) What is the probability that their first child would be normal? (2) What is the probability that their first two children would have CF? (3) If they would like to have five children, what is the probability that at least two of them would be normal?
In: Biology
6. Compare and contrast the function and structure of the uterine stratum basalis and functionalis.
7. Compare and contrast the structure and function of the vagina and cervix.
In: Biology
1.What is the name for the covalent bonds that create the Nucleic Acid backbone?
2.Define Complementarity as it is used in nucleic acid base pairing and explain how complimentary base pairing is the basis for making faithful copies of DNA from DNA templates and RNA from DNA templates.
In: Biology
Before you five types of lipids. Represent and
illustrate all of them. What are the hydrophylic and hydrophobic
parts in each of them?
1) cholesterol
2) gangelioside
3) sphingomyelin
4) galactosylcerebroside
5)phosphatidylethanolamine
Thank you very much!
In: Biology
Using the following powerpoint answer the following questions on the study guide.
THESE ARE THE QUESTIONS:
1.)Be able to explain why ER signal sequences are thought to be necessary and sufficient
2.)Know how the cell regulates the activity of transporters, receptors, and enzymatic proteins.
3.)Be able to explain, in moderate detail, the three main mechanisms of protein transport into organelles.
4.)Be able to describe the transport of soluble, single-pass and double-pass transmembrane proteins across the ER membrane.
5.)Know what happens to improperly folded and incompletely modified proteins.
6.)Be able to explain how the different types of ion channels are used by neurons to receive and transmit information.
7.)Be able to explain the formation of clathrin-coated vesicles
CHAPTER CONTENTS
MEMBRANE-ENCLOSED ORGANELLES
PROTEIN SORTING
VESICULAR TRANSPORT
SECRETORY PATHWAYS
ENDOCYTIC PATHWAYS
MEMBRANE-ENCLOSED ORGANELLES
Eukaryotic Cells Contain a Basic Set of Membrane-enclosed Organelles
PROTEIN SORTING
Proteins Are Transported into Organelles by Three Mechanisms
Signal Sequences Direct Proteins to the Correct Compartment
Proteins Enter the Nucleus Through Nuclear Pores
Proteins Unfold to Enter Mitochondria and Chloroplasts
Proteins Enter Peroxisomes from Both the Cytosol and the Endoplasmic Reticulum
Protein Sorting
Proteins are made in the cytoplasm (by ribosomes either free in the cytosol or on the rough ER).
Proteins must then be transported either into the RER lumen, or to another site in the cell.
How are these new proteins sorted?
Protein Sorting
Cytosol
Nucleus
Mitochondria and Chloroplasts
Endoplasmic Reticulum
Soluble proteins (lumen)
Membrane proteins
3 main mechanisms for importing proteins into membrane-bound organelles
PROTEIN SORTING
Proteins Are Transported into Organelles by Three Mechanisms
Signal Sequences Direct Proteins to the Correct Compartment
Proteins Enter the Nucleus Through Nuclear Pores
Proteins Unfold to Enter Mitochondria and Chloroplasts
Proteins Enter Peroxisomes from Both the Cytosol and the Endoplasmic Reticulum
Protein Signal Sequences
Signal sequences are a stretch of amino acids typically 15-60 amino acids long found on the N-terminal of a newly synthesized protein
They are often (but not always) removed from the finished protein once they have been sorted correctly.
Signal sequences allow the newly synthesized proteins to be recognized and delivered to the proper place.
The exact sequence of the signal sequence does not seem to be as important as its physical propeties (hydrophobicity, placement of charged amino acids…)
Signal sequences are necessary and sufficient for protein sorting.
Proteins without a signal sequence stay in the cytosol
Protein Signal Sequences
Table 15–3 Some Typical Signal Sequences
FUNCTION OF SIGNAL EXAMPLE OF SIGNAL SEQUENCE
Import into ER +H3N-Met-Met-Ser-Phe-Val-Ser- Leu-Leu-Leu-Val-Gly-Ile-Leu-Phe- Trp-Ala-Thr-Glu-Ala-Glu-Gln- Leu-Thr-Lys-Cys-Glu-Val-Phe-Gln-
Retention in lumen of ER -Lys-Asp-Glu-Leu-COO–
Import into mitochondria +H3N-Met-Leu-Ser-Leu-Arg-Gln- Ser-Ile-Arg-Phe-Phe-Lys-Pro-Ala- Thr-Arg-Thr-Leu-Cys-Ser-Ser- Arg-Tyr-Leu-Leu-
Import into nucleus -Pro-Pro-Lys-Lys-Lys-Arg-Lys-Val-
Import into peroxisomes -Ser-Lys-Leu-
PROTEIN SORTING
Proteins Are Transported into Organelles by Three Mechanisms
Signal Sequences Direct Proteins to the Correct Compartment
Proteins Enter the Nucleus Through Nuclear Pores
Proteins Unfold to Enter Mitochondria and Chloroplasts
Proteins Enter Peroxisomes from Both the Cytosol and the Endoplasmic Reticulum
PROTEIN SORTING
Proteins Are Transported into Organelles by Three Mechanisms
Signal Sequences Direct Proteins to the Correct Compartment
Proteins Enter the Nucleus Through Nuclear Pores
Proteins Unfold to Enter Mitochondria and Chloroplasts
Proteins Enter Peroxisomes from Both the Cytosol and the Endoplasmic Reticulum
PROTEIN SORTING
Proteins Are Transported into Organelles by Three Mechanisms
Signal Sequences Direct Proteins to the Correct Compartment
Proteins Enter the Nucleus Through Nuclear Pores
Proteins Unfold to Enter Mitochondria and Chloroplasts
Proteins Enter Peroxisomes from Both the Cytosol and the Endoplasmic Reticulum
Import into the Peroxisomes
Enzymes that break down toxins, fatty acids and alcohol are imported into peroxisomes.
Imported using three a.a. signal sequence, receptor proteins and protein translocators (similar to mitochondrial proteins).
The proteins do not unfold first
Exact mechanism still not clear.
PROTEIN SORTING
Proteins Enter the Endoplasmic Reticulum While Being Synthesized
Soluble Proteins Made on the ER Are Released into the ER Lumen
Start and Stop Signals Determine the Arrangement of a Transmembrane Protein in the Lipid Bilayer
Import into the ER
Two types of proteins are imported into the ER:
Water-soluble proteins
These are destined for either secretion or for the lumen of an organelle
Prospective trans-membrane proteins
These are destined to reside in the membrane of the ER or other cellular organelle or the Plasma membrane
Import into the ER
Unlike Nuclear, Mitochondrial and Chloroplast proteins, most of the ER proteins are threaded into the ER while being translated.
Membrane-bound ribosomes are located on the surface of the rough ER and make proteins that are being translocated across the ER membrane
Free ribosomes not located on any membranes make all other proteins
PROTEIN SORTING
Proteins Enter the Endoplasmic Reticulum While Being Synthesized
Soluble Proteins Made on the ER Are Released into the ER Lumen
Start and Stop Signals Determine the Arrangement of a Transmembrane Protein in the Lipid Bilayer
Import into the ER
While the growing polypeptide chain is being produced, a signal-recognition particle (SRP) binds to the ER signal sequence.
The SRP is then recognized by an SRP receptor on the surface of the ER.
The SRP dissassociates and the SRP receptor brings the ribosome to a translocation channel where the new polypeptide enters the ER lumen while it is being translated.
Once inside the ER lumen, a signal peptidase cleaves off the signal sequence
PROTEIN SORTING
Proteins Enter the Endoplasmic Reticulum While Being Synthesized
Soluble Proteins Made on the ER Are Released into the ER Lumen
Start and Stop Signals Determine the Arrangement of a Transmembrane Protein in the Lipid Bilayer
Transmembrane Protein import
Remain embeded in membrane of ER – not released to the lumen
Single membrane spanning proteins contain a sequence of hydrophobic amino acids called a stop-transfer sequence that causes the protein to be released by the translocation channel and inserted into the membrane.
N-terminal remains in lumen, C-terminal in cytosol
15_15_into_ER_membr.jpg
Transmembrane Protein import
Multiple membrane spanning proteins have an internal signal sequence (not an N-terminal sequence) that doubles as a start-transfer sequence.
When the channel recognizes the start-transfer sequence, it causes the protein to translocate in the other direction across the membrane. Hydrophobic a-helices span the membrane until a stop-transfer sequence is recognized.
15_16_double_pass.jpg
Vesicular Transport
Entry into ER often only first step to final destination
Initial destination after ER is Golgi complex
Transport from ER to Golgi, between Golgi stacks, and from Golgi to either lysosomes or cell surface carried out by transport vesicles
Transport vesicles continually bud off from one compartment and fuse to another
Transport can occur in forward and reverse directions
Vesicles are specific for the distinct proteins and lipids they carry
VESICULAR TRANSPORT
Transport Vesicles Carry Soluble Proteins and Membrane Between Compartments
Vesicle Budding Is Driven by the Assembly of a Protein Coat
Vesicle Docking Depends on Tethers and SNAREs
VESICULAR TRANSPORT
Transport Vesicles Carry Soluble Proteins and Membrane Between Compartments
Vesicle Budding Is Driven by the Assembly of a Protein Coat
Vesicle Docking Depends on Tethers and SNAREs
15_18_Clathrin_EM.jpg
Clathrin-Coated Vesicles
Clathrin-coated vesicles are the best studied
Involved in both the outward secretory and inward endocytotic pathways.
Adaptins secure the clathrin coat to the vesicle membrane and help select the cargo molecules for transport.
Adaptins trap cargo receptors that bind to the cargo molecules.
Dynamin molecules bind to GTP (energy carrier) and pinch off the cell membrane into a vesicle.
15_19_Clathrin_vesicle.jpg
VESICULAR TRANSPORT
Transport Vesicles Carry Soluble Proteins and Membrane Between Compartments
Vesicle Budding Is Driven by the Assembly of a Protein Coat
Vesicle Docking Depends on Tethers and SNAREs
Vesicular transport
Coated vesicles are transported along fibers of the cytoskeleton to their final destination.
The vesicle recognizes and docked with its correct organelle through a family of transmembrane proteins called SNAREs.
v-SNAREs are on the transport vesicles and their complementary t-SNAREs are found on the target membrane of the organelle.
Each organelle and each type of transport vesicle is thought to contain unique SNAREs.
Once the SNAREs recognize each other, the vesicle docks with the organelle and membrane fusion occurs.
15_20_SNAREs.jpg
SECRETORY PATHWAYS
Most Proteins Are Covalently Modified in the ER
Exit from the ER Is Controlled to Ensure Protein Quality
The Size of the ER Is Controlled by the Demand for Protein
Proteins Are Further Modified and Sorted in the Golgi Apparatus
Secretory Proteins Are Released from the Cell by Exocytosis
Secretory Pathways
Exocytosis is the process by which newly made proteins, lipids and carbohydrates are delivered to the cell surface by transport vesicles which fuse with the cell membrane.
Proteins are first chemically modified in the ER – disulfide bonds are formed and glycosylation occurs (carbohydrates are covalently added to an Asparagine nitrogen (N-linked))
15_22_glycosylated_ER.jpg
SECRETORY PATHWAYS
Most Proteins Are Covalently Modified in the ER
Exit from the ER Is Controlled to Ensure Protein Quality
The Size of the ER Is Controlled by the Demand for Protein
Proteins Are Further Modified and Sorted in the Golgi Apparatus
Secretory Proteins Are Released from the Cell by Exocytosis
Secretory Pathways
Proteins without an ER retention signal (on the C-terminus) are packaged into transport vesicles and sent to the Golgi.
Improperly folded or incompletely modified proteins are retained by chaperone proteins in the ER and degraded.
Cystic Fibrosis is caused by a mutation that leads to misfolding of a chloride channel that leads to its not being exported
SECRETORY PATHWAYS
Most Proteins Are Covalently Modified in the ER
Exit from the ER Is Controlled to Ensure Protein Quality
The Size of the ER Is Controlled by the Demand for Protein
Proteins Are Further Modified and Sorted in the Golgi Apparatus
Secretory Proteins Are Released from the Cell by Exocytosis
Secretory Pathways
An accumulation of misfolded proteins in the ER triggers the unfolded protein response (UPR).
The UPR stimulates increased production of ER chaperone proteins and increases the size of the ER.
SECRETORY PATHWAYS
Most Proteins Are Covalently Modified in the ER
Exit from the ER Is Controlled to Ensure Protein Quality
The Size of the ER Is Controlled by the Demand for Protein
Proteins Are Further Modified and Sorted in the Golgi Apparatus
Secretory Proteins Are Released from the Cell by Exocytosis
Golgi Apparatus
The Golgi Apparatus sorts and further modifies proteins.
After traveling through the Golgi stacks, proteins are packed into transport vesicles and sent to the cell membrane.
SECRETORY PATHWAYS
Most Proteins Are Covalently Modified in the ER
Exit from the ER Is Controlled to Ensure Protein Quality
The Size of the ER Is Controlled by the Demand for Protein
Proteins Are Further Modified and Sorted in the Golgi Apparatus
Secretory Proteins Are Released from the Cell by Exocytosis
Exocytosis and Endocytosis
Exocytosis - mechanism for exporting proteins and lipids out of the cell
Endocytosis - mechanism for importing molecules into the cell
Two secretory pathways in secretory cells
All cells contain a constitutive secretory pathway for delivering plasma membrane proteins and lipid to plasma membrane.
Also used for secretion of some proteins into blood e.g. albumin from liver cells
Specialized cells like hormone producing cells also contain a regulated secretory pathway where secretory vesicles are stored at the cell membrane and released all at once.
This allows controlled secretion of large quantities of protein in response to specific stimuli
15_28_trans_Golgi_net.jpg
15_29_Secretory_vesicl.jpg
Endocytic pathways
Pinocytosis (“cellular drinking”) - uptake of fluid and molecules via small (<150nm diameter) vesicles. Occurs in all cells
Phagocytosis (“cellular eating”) - uptake of large particles e.g. microorganisms and cell debris via large (>250nm diameter) vesicle. Only occurs in specialised cells - phagocytic cells e.g. macrophages
ENDOCYTIC PATHWAYS
Specialized Phagocytic Cells Ingest Large Particles
Fluid and Macromolecules Are Taken Up by Pinocytosis
Receptor-mediated Endocytosis Provides a Specific Route into Animal Cells
Endocytosed Macromolecules Are Sorted in Endosomes
Lysosomes Are the Principal Sites of Intracellular Digestion
White blood cell ingests bacteria
Macrophage engulfs red blood cells
ENDOCYTIC PATHWAYS
Specialized Phagocytic Cells Ingest Large Particles
Fluid and Macromolecules Are Taken Up by Pinocytosis
Receptor-mediated Endocytosis Provides a Specific Route into Animal Cells
Endocytosed Macromolecules Are Sorted in Endosomes
Lysosomes Are the Principal Sites of Intracellular Digestion
ENDOCYTIC PATHWAYS
Specialized Phagocytic Cells Ingest Large Particles
Fluid and Macromolecules Are Taken Up by Pinocytosis
Receptor-mediated Endocytosis Provides a Specific Route into Animal Cells
Endocytosed Macromolecules Are Sorted in Endosomes
Lysosomes Are the Principal Sites of Intracellular Digestion
Receptor-mediated endocytosis
Pinocytosis is indescriminate - cells must also have a way to internalize selectively
Selected macromolecules are taken up by cell via specific interaction with a receptor on the cell surface - receptor mediated endocytosis
Clathrin-coated vesicles are involved
Examples are:
Cholesterol transported in blood complexed to protein - low density lipoprotein (LDL) which binds to receptors on cell surface and is internalized. Within endosomes LDL and receptor dissociate, LDL transferred to lysosome, degraded and cholesterol released into cytosol.
Other examples include insulin and other signaling hormones, iron and vitamin B12.
ENDOCYTIC PATHWAYS
Specialized Phagocytic Cells Ingest Large Particles
Fluid and Macromolecules Are Taken Up by Pinocytosis
Receptor-mediated Endocytosis Provides a Specific Route into Animal Cells
Endocytosed Macromolecules Are Sorted in Endosomes
Lysosomes Are the Principal Sites of Intracellular Digestion
Possible fates for proteins
after endocytosis
Most receptors specifically retrieved from endosomes to same area of plasma membrane – recycling
If not retrieved, receptors follow pathway from endosomes to lysosomes for degradation
Some receptors are returned to a different area of plasma membrane - transcytosis. This transports cargo molecules from one extracellular space to another
In: Biology
Many potent toxins and lethal poisons exert their effects by interfering with energy production in the cell. Select any such molecule (that interferes with energy production), and discuss which metabolic pathway it affects, particularly which enzyme(s) and how. -----> PLEASE TYPE 250 WORDS & INCLUDE 1 - 2 SOURCES, NO DIAGRAMS
In: Biology
A meiosis occurs in which a resulting egg contains 14 chromosomes from the father and 9 chromosomes from the mother. How many possible chromosomal combinations could lead to this outcome?
What is the probability that any given egg will contain 14 chromosomes from the father and 9 chromosomes from the mother?
In: Biology
Cystic Fibrosis Transmembrane conductance Regulator (CFTR) is an ABC transporter that allows passage of chloride ions across the plasma membranes of epithelial cells. Mutations in the gene for CSTR cause a decrease in fluid and salt secretion by CFTR and result in cystic fibrosis. In 70% cases of the disease, the mutation is a deletion of a Phe residue at position 508. The mutant protein folds incorrectly, which interferes with its insertion in the plasma membrane, and as a consequence, the movement of chloride ions across the membranes is impaired. Malfunctioning CFTR results in blocked and heavy secretion from the exocrine glands (pancreas, sweat glands, bile ducts and vase deferens). Cystic fibrosis patients produce dehydrated mucus that accumulates in the lungs and leads to chronic infections that damage the lungs. Respiratory failure is commonly the cause of death in people with cystic fibrosis.
In this discussion, explain a genetic disease that you have investigated upon. Describe the genetic defect [specifically which protein is involved] and how it affects the body’s metabolism and physiology. (PLEASE TYPE 250-300 WORDS & INCLUDE 1 - 2 SOURCES, NO DIAGRAMS)
In: Biology
Monsoon rains in India and in the North American Southwest are both caused by the land heating faster than the water, which causes moisture to be drawn over the land from neighboring bodies of water.
True
False
In: Biology
What are three different ways to show that a specific protein (e.g., protein X) physically interacts with another specific protein (e.g., protein Y)?
In: Biology
Write about COLOR BLINDNESS
•Who discovered the disease
•When, where, and how was the disease discovered
•Are there treatments or cures for the disease
•Describe relevant information regarding how (if) the treatments or
cure were discovered.
•Provide a timeline of important events and individuals involved in
the discovery and progression of knowledge regarding the
disease.
Be sure to include information about the following. Write in paragraph format, include citations from your sources where you found the information. Minimum 300 words.
In: Biology