Exam 1
Microtubule Function
(1) internal i. cellular trafficking ii. movement of chromosomes during cell division (mitotic spindle) (2) external i. movement of extracellular materials (cilia) ii. propulsion of sperm (flagella)
Nucleolus organization
(1)nucleolar organizer DNA (NO) à encodes rRNA (2) pars fibrosa (PF) --> rRNA (3) pars granulosa (PG) --> maturing ribosomes = (rRNA + proteins)
Hierarchy of cellular components levels
(from top to bottom) L1 = small organic molecules L2 = macromolecules L3 = supramolecular structures L4 = organelles and other structures L5 = the cell
DNA synthesis (S Phase)
(semi-conservative replication) One strand of the parent double helix is conserved in each new DNA molecule
Surface Specialization Cilia
(~5-10µm long) and flagella (much longer) 1. motile 2. also known as axoneme 3. 9 doublets of microtubules surrounding 2 single microtubules (9+2) 4. motor protein is axonemal dynein 5. requires ATP as energy source 6. supporting proteins maintain microtubular arrangement 7.basal body a. cytoplasmic base of axoneme b. composed of 9 triplets of microtubules with no central microtubules (9+0)
collagen types
*table 17.2* slide 17 ECM ppt
Lysosomes
-- Contain many hydrolytic enzymes (acid hydrolases) -- H+ pumps maintain acidic internal environment -- Contains over 40 hydrolytic enzymes-lipases, proteases, nucleases and carbohydrases
Lysosomes
-- Small organelles, but readily visualized by EM or light microscopy -- Form by budding off of Golgi complex -- Enzymes are active in acidic environment Functions: --immunological defense --cellular recycling --apoptosis (via autolysis)
Smooth Endoplasmic reticulum
-- no ribosomes - no protein synthesis -- synthesis of lipids and steroids -- glycogen metabolism -- detoxification of some drugs, --- xenobiotics --- sequesters and releases Ca2+ ions in muscle cells
Preparation from Mitosis occurs in what phase of the cell cycle? A. G1 B. G2 C. GO D. G3
B. G2
rough endoplasmic reticulum (RER)
--- surface is associated with many ribosomes --- growing polypeptide chain glycosylated and released in lumen --- proteins packaged into vesicle and released
plasma membrane function
--Acts as dynamic barrier between internal and external environment --Maintains chemical and electrical gradient --Basic structural unit-phospholipid bilayer- fluid mosaic membrane
amino acid affect on protein
--Amino acid sequence determines the three-dimensional structure, thus the function, of a protein --With 20 different amino acids, a nearly infinite variety of protein sequences is possible
Intermediate filaments
--Fibrous, not globular protein --More stable --Made up of different protein subunits in different cells --Provide structural strength more diverse in composition than other cytoskeletal elements
Example of Medical application
--Inhibitory compounds used in cancer chemotherapy to block activity of mitotic spindle in rapidly growing tumor cells --Class V intermediate filaments defects are found in muscular dystrophy
Human cells have three basic parts
--Plasma membrane—flexible outer boundary --Cytoplasm—intracellular fluid containing organelles --Nucleus—control center
Macromolecules/Polymers
--Proteins (Polymers of amino acids) --Polysaccharides (Polymers of sugars, carbohydrates) --Nucleic acids (polymers of nucleotides) --Lipids (made of variety of different molecules) Note: Except for lipids, these macromolecules are also called polymers
Examples of Medical Application
--Proteins of Zonula Occludens provide targets for by some bacteria which causes food poisoning --Blistering diseases involving the epidermis are due to abnormal desmosome function
Monomeric nucleotides
--Sources of chemical energy in cell (usually ATP) --Cell signaling (various nucleotides
Nucleic acids are
--are the largest molecules in the body. --Nucleic acid monomers called nucleotides Composed of nitrogen base, a pentose sugar, and a phosphate group
Domains
--compact units connected by the short peptide chains --relatively independent on other domains --may exhibit different biological activities Note: Proteins with multiple functions usually have a separate domain for each function. --eg. for proteins that are enzymes, one domain carries out catalytic activity another regulates enzymatic activity.
Peroxisomes (Microbodies) function
--contain enzymes used for detox of harmful substances --oxidases à neutralize free radicals and other toxins, generating H2O2 --catalases --> H2O2 --> H2O + O2 --also oxidize long-chain fatty acids (up to 22 carbon atoms)
Glycoproteins
--covalently linked sugar residues on outside of cell A. sugar act as recognition sites B. important as self determinant for immune system
Nuclear envelope
--double membrane: outer layer continuous with endoplasmic reticulum --nuclear pores: regulate passage of material between nucleus and cytoplasm
Golgi apparatus function
--further post-translational modifications --protein sorting, packaging, trafficking --processing and packaging of proteins secreted from RER
Quaternary structure
--level of organization concerned with subunit interactions and assembly --specifically to multimeric proteins --Some proteins consist of multiple identical subunits; others, like hemoglobin, contain two or more types of polypeptides
Integrins are:
--plasma proteins --Binding sites for extracellular matrix components: -Collagen -Fibronectin -laminin
Tertiary structure
--reflects the unique aspect of the amino acid sequence because it depends on interactions of the R groups --neither repetitive nor easy to predict --results from the sum of hydrophobic residues avoiding water, hydrophilic residues interacting with water, the repulsion of similarly charged residues, and attraction between oppositely charged residues eg. Ribonuclease
Peroxisomes structure
--resemble lysosomes --may contain dark staining crystalline core composed of enzymes
Golgi complex (apparatus)
--stacks of flattened sacs --completes glycosylation of glycoproteins Polarity: a)cis face = "receiving side" --> fuses with vesicles released from RER containing proteins b)trans face = "shipping side" --> processed proteins secreted in vesicles bound for cell membrane
nucleic acids uses
--storage of genetic information-DNA --transient expression of genetic information-RNA --protein synthesis-RNA
Carrier molecules
-For protein synthesis, amino acids are linked to carriers called transfer RNA (tRNA) -Sugars (often glucose) that form polysaccharides are activated by linking them to ADP (adenosine diphosphate), or UDP (uridine diphosphate) -For nucleic acids the nucleotides themselves are high-energy molecules (ATP, GTP)
Hemidesmosomes
-instead of cadherins attaching adjacent cells, integrins attach cell to components of the extracellular matrix. It anchors cytoskeleton to the basal lamina.
Adherens junctions (zonula adherens)
-membrane proteins (Ca++ dependent cadherin) of adjacent cells bind to adhere cells to each other -actin microfilaments in cell cortex anchor cadherins transmembrane glycoproteins of each cell that interact in the presence of calcium. It strengthens the tissue.
Matching Macromolecule: 1. DNA 2. Cellulose 3. Hemoglobin 4. Glycogen 5. Triglyceride 6. Starch 7. Collagen Monomer: A. Glucose B. Nucleotide C. Amino Acid D. Fatty acids
1 = B 2 = A 3 = C 4 = A 5 = D 6 = A 7 = C
Microfilaments function
1) structural support (e.g. cell cortex) (2) cleavage furrow during cell division (dividing cells) (3) structural basis of microvilli (e.g. in gut epithelium) (4) muscle contraction (muscle cells) • (4) amoeboid movement (phagocytic cells) • (5) cytoplasmic streaming (some cells)
Proteoglycans
1. Core protein 2. Attached glycosaminoglycans a. dermatan sulfate b. chondroitin sulfate c. keratan sulfate d. heparan sulfate
Regulation of the Cycle (internal)
1. Cyclins: Proteins which bind to specific kinases (cyclin-dependent kinases - CDKs) to regulate events of interphase. All eukaryotes have multiple cyclins, each of which acts during a specific stage of the cell cycle. (In organisms with multiple CDKs, each CDK is paired with a specific cyclin.) For example: M- phase cyclins form M-CDK complexes and drive the cell's entry into mitosis.
S Phase
1. DNA synthesis 2. 6-8 hours 3. semiconservative replication maintains integrity of genetic information 4. centrioles required for mitotic spindle replicated
Cell cycle regulation
1. G2-M transition: influenced by cell size, DNA damage, DNA replication 2. Metaphase-Anaphase transition: influenced by chromosome attachments to spindle 3. Restriction Point (start): influenced by growth factors, nutrients, cell size, DNA damage
Hierarchy of cellular components
1. Small organic molecules are synthesized from simple inorganic substances and are polymerized to from macromolecules. 2. The macromolecules then assemble into supramolecular structures that make up organelles and other cellular structures and, ultimately, the cell itself.
Components of ECM
1. Structural proteins such as collagens and elastins, which provide strength and flexibility 2. Protein-polysaccharide complexes, proteoglycans, that provide the matrix 3. Adhesive glycoproteins, fibronectins laminins, and integrins that allow cells to attach to the matrix
Functions of membrane proteins
1. Transport 2. Receptors for signal transduction 3. Attachment to cytoskeleton and extracellular matrix 4. Enzymatic activity 5. Intercellular joining 6. Cell-cell recognition
mitochondrion structure
1. double-membrane -inner membrane folds called cristae -inner membrane contains carrier proteins of electron transport system and ATP synthase 2. matrix contains enzymes of TCA cycle and b-oxidation of fatty acids 3. contains circular DNA and ribosomes - similar to prokaryotic cells 4. semi-autonomous
G2 Phase
1. gap 2 or post synthetic 2. relatively uniform in length; 3-6 hours 3. preparation for mitosis 4. checkpoint for repair of DNA
GO Phase
1. in cells that can exit the cycle for varying lengths of time a. cardiac muscle and neurons permanently exit 2. Entered from G1
Glycosaminoglycans (GAGs) or mucopolysaccharides
1. linear polysaccharides formed of repeating disaccharides a. uronic acid (can be glucuronic or iduronic acid) b. hexosamine (can be glucosamine or galactosamine) 2. covalently linked to core protein to form proteoglycan 3. exception: hyaluronic acid not linked to protein 4. abundant sulfate and carboxyl groups make molecules hydrophilic and negatively charged
Apoptosis (Embryonic development)
1. normal reorganization of tissues 2. example: developing hand and foot
Karyokinesis steps
1. prophase 2. metaphase 3.anaphase 4. telophase
Macromolecules synthesis
1. stepwise polymerization of similar or identical monomers 2. Addition occurs with the removal of a water molecule ( condensation reaction ) 3. Monomeric units are joined together by activated monomers before condensation occurs 4. Activation involves coupling of monomer to a carrier molecules forming activated monomer 5. Energy needed is ATP 6. Because of the way they are synthesized, have an inherent directionality. Both ends are different
Collagen synthesis (ECM)
1. synthesis (RER) → preprocollagen, primarily glycine 2. hydroxylation (RER) of proline and lysine (vitC required) 3. glycosylation (RER) to form triple helix → procollagen 4. exocytosis into extracellular space 5. proteolytic processing → tropocollagen 6. cross-linking (covalent lysine-hydroxylysine cross-linkage, Cu required) → collagen fibrils
Endomembrane system function
1. synthesis of lysosomes, secreted, & membrane proteins -nucleus --> mRNA transcription -RER --> translation of mRNA; polypeptide modification -transport vesicles --> from RER to Golgi -Golgi --> further modification, packaging, and shipping a) lysosomes OR b) transport/secretory vesicles carry protein to plasma membrane -inner mitochondrial membrane - electron transport chain
Apoptosis (Adult tissue)
1. to balance cell divisions 2. removes cells that are damaged or ineffective 3. nucleus condenses and breaks up 4. cell surface blebs and becomes target for phagocytosis 5. does not initiate an inflammatory response
collagen organization
1. type I - ubiquitous; largest fibers 2. type II - hyaline and elastic cartilage: fibrils only 3. type III - reticular 4. type IV - no fibers; meshwork; in basal lamina
G1 Phase
1. variable in length 2. gap 1 or presynthetic phase 3. cell growth 4. protein synthesis 5. checkpoint prior to entry into S a. is environment favorable for division b. is DNA intact
Organelles of Eukaryotes
1.Nucleus 2.Endoplasmic reticulum 3.Golgi complex (apparatus) 4.Lysosomes 5.Mitochondrion 6.Peroxisomes 7.Ribosomes
Surface Specialization Sterocilia
1.long branched microvilli 2.increase surface area for transport across membrane 3.increase surface area for transport across membrane
Plasma membrane proteins are amphipathic
3 types: --Integral proteins --Extrinsic (peripheral) proteins --Glycoproteins
axoneme complex
9 doublets + 2 singlets (9 + 2 arrangement) forms body of cilia and flagella
Secondary Structure
Either an alpha helix or beta pleated sheet. Determined by hydrogen binding within the polypeptide
Glycogen is found in plant cells? A. True B. False
B. False
Hydrogen bonds are very strong and are very hard to break. A. True B. False
B. False
Internal regulation of cell cycle is dependent on different types of growth factors. A. True B. False
B. False
Transcription and translation both occur in the cytoplasm? A. True B. False
B. False
Base pairing and genetic codon
A + T/U = 2 hydrogen binds C + G = 3 hydrogen bonds
sister chromatid split and migrate toward the opposite pole A) Anaphase B) Telophase C) prophase D) Metaphase
A) Anaphase
What structural level is represented by the sequence of amino acids in a polypeptide chain? A) primary structure B) secondary structure C) tertiary structure D) quaternary structure
A) primary structure
Which of the following structures would aid a cell in allowing absorption? MACA A) stereocilia B) microvilli C) cilia D) flagella
A) stereocilia B) microvilli
Identify the intramolecular interaction or bonding found in tertiary structure of proteins? MACA A. Covalent B. Hydrophobic C. Hydrogen D. Ionic
A. Covalent B. Hydrophobic C. Hydrogen D. Ionic
Hemoglobin molecule is made of : A. Three polypeptide chain A. Four poly peptide chain B. Only one chain C. None of the above
A. Four poly peptide chain
Surface Specialization Microvilli, Sterocilia, Cilia
A. Function: 1.to increase surface area 2. to move substances across surface
Which of the following characteristics for mitochondria is correct? MACA A. Has Inner membrane named Cristae B. Has its own DNA C. Contains ribosomes D. Enzymes for TCA E. It is a storage of glycogen
A. Has Inner membrane named Cristae B. Has its own DNA C. Contains ribosomes D. Enzymes for TCA
Type II collagen fiber is found in: MACA A. Hyaline cartilage B. Basal lamina C. Elastic cartilage D. Basement membrane
A. Hyaline cartilage C. Elastic cartilage
What is the type of the bond between amino acids in a primary structure? MACA A. Peptide B. covalent bond C. Hydrophobic interaction D. Noncovalent bond
A. Peptide B. covalent bond
Extracellular Matrix function
A. Reservoir for water, ions, nutrients, hormones, cell signaling molecules, etc. B. Maintain strength and rigidity of tissue C. Maintain shape of tissue D. Medium through with nutrients and metabolic wastes exchanged
Protein structure represented by alpha-helices or beta-sheets. A. Secondary structure B. Primary structure C. Tertiary structure D. Quaternary structure
A. Secondary structure
Basal lamina
A. Specialized extracellular matrix attaching epithelia to connective tissue B. Type IV collagen fibers in matrix C. Laminin 1. adhesive molecule of matrix 2. attachment sites for epithelial integrins and type IV collagen
Apoptosis does not cause inflammation. A. True B. False
A. True
Cancerous cells can divide so rapidly that they will often produce a glycocalyx that is different than the other cells in the body. This may result in cells of the immune system recognizing the tumorous cells as foreign and destroying them A. True B. False
A. True
Cholesterol is the most important for control of fluidity of membrane? A. True B. False
A. True
Collagen is a fibrous protein while hormones are Globular proteins A. True B. False
A. True
Glycogen, the storage form of glucose, is primarily stored in skeletal muscle and liver cells. A. True B. False
A. True
Reticular fibers are type III collagen fibers are produced by fibroblasts. A. True B. False
A. True
Integral proteins
A. extend through entire membrane B. transmembrane proteins
Nitrogenous bases in DNA
Adenine (A) Thymine (T) Cytosine (C) Guanine (G) A & G = purines C & T = pyrimidines
nitrogenous bases IN RNA
Adenine (A), Uracil (U), Cytosine (C), Guanine (G) A & G = purines C & U = pyrimidines
Generalized (Typical) Cell
All cells have some common structures and functions
Which organelle is responsible for processing and packaging proteins destined for export from the cell? A) endoplasmic reticulum B) Golgi apparatus C) lysosomes D) peroxisomes
B) Golgi apparatus
Chromosomes uncoil to form chromatin. A) Anaphase B) Telophase C) prophase D) Metaphase
B) Telophase
The electron microscope has revealed that one of the components within the cell consists of pinwheel array of 9 triplets of microtubules arranged to form a hollow tube. This structure is a ________. A)Microvilli B)centriole C) chromosome D) ribosome
B)centriole
Which of the following cytoskeletal elements is necessary for cleavage formation? A. Microtubules B. Actin filaments C. Centrioles D. Tubulin molecules
B. Actin filaments
You expect to find many gap junctions in ........ Than in .......... A. Epithelium..............Cardiac muscle B. Cardiac muscle....... Epithelium
B. Cardiac muscle....... Epithelium
Collagen is only secreted by fibroblast cells. A. True B. False
B. False
Which of the following is correct about Proteoglycans: A. They are long chains of polysaccharides called GAGS B. Gags plus proteins makes proteoglycans C. Chondroitin sulfate is a proteoglycan C. Dermatan sulfate is a proteoglycans D. All of the above are correct
B. Gags plus proteins makes proteoglycans
Plasma membrane proteins with covalently bound carbohydrates are called: A. Cholesterol B. Glycoproteins C. Phosphoproteins D. Phospholipids
B. Glycoproteins
Desmosomes bound to ... A. Actin filament inside the cell B. Intermediate filaments C. Flagella
B. Intermediate filaments
Colchicine is a drug that can prevent the formation of microtubules. Which is the most likely effect colchicine would have on cell division? A. It will enhance mitosis by moving chromosome toward the spindle equator. B. It will arrest mitosis by preventing the formation of spindle microtubules. C. It would have little or no effect on mitosis. D. It would delay mitosis by preventing S phase.
B. It will arrest mitosis by preventing the formation of spindle microtubules.
In which stage of mitosis do the identical sets of chromosomes line up along the midline or equator of the cell? A. Prophase B. Metaphase C. Anaphase D. Telophase
B. Metaphase
Gags are made of: A. polypeptides B. Polysaccharides C. Polynucleotides D. None of the above
B. Polysaccharides
Two or more polypeptide chains, each with its own tertiary structure. A. Secondary structure B. Primary structure C. Tertiary structure D. Quaternary structure
B. Primary structure
Which one of the following is an example of a disaccharide? MACA A. Fructose B. Sucrose C. Lactose D. galactose
B. Sucrose C. Lactose
Which of the followings have high affinity for silver staining? MACA A. Type I Collagen fibers B. Type III collagen fibers C. Elastic fibers D. Reticular fibers
B. Type III collagen fibers D. Reticular fibers
The plasma membrane is composed of A. a bilayer of proteins. B. a bilayer of phospholipids. C. carbohydrate molecules. D. carbohydrates and proteins. E. carbohydrates and lipids
B. a bilayer of phospholipids.
Stereocilia: A. are short B. are made of microvilli C. are motile D. none of the above
B. are made of microvilli
The genetic information is coded in DNA by the ________. A. regular alteration of sugar and phosphate molecules B. sequence of the nucleotides C. three-dimensional structure of the double helix D. arrangement of the histones
B. sequence of the nucleotides
What is the ratio of fatty acids to glycerol in triglycerides? A) 1:1 B) 2:1 C) 3:1 D) 4:1
C) 3:1
Starch is a ________. A) monosaccharide B) disaccharide C) polysaccharide D) triglyceride
C) polysaccharide
Centrioles move to opposite ends of the cell A) Anaphase B) Telophase C) prophase D) Metaphase
C) prophase
Nuclear envelope and nucleolus disintegrate A) Anaphase B) Telophase C) prophase D) Metaphase
C) prophase
Phospholipids make up most of the lipid part of the cell membrane. Since water exists on both the outside and inside of a cell, which of the following phospholipid arrangements makes the most sense? A) two back-to-back phospholipid layers with the non-polar tails facing out on both sides B) a single layer of phospholipids with the polar heads facing outside the cell C) two back-to-back phospholipid layers with the polar heads facing out on both sides D) a single layer of phospholipids with the polar heads facing inside the cell
C) two back-to-back phospholipid layers with the polar heads facing out on both sides
Mitosis includes: A. Cytokinesis B. Karyokinesis C. Both above
C. Both above
The most abundant protein in the body is? A. Elastin B. Laminin C. Collagen D. Integrin E. fibronectin
C. Collagen
Mitochondria ________. A. Contain digestive enzymes called acid hydrolyses B. Are single-membrane structures involved in the breakdown of ATP C. Contain some of the DNA and RNA code necessary for their own function D. synthesize proteins for use outside the cell
C. Contain some of the DNA and RNA code necessary for their own function
Cardiac muscle tissue undergoes a significant amount of physical stress due to its contractions. You would expect to see relatively large numbers of which of the following embedded within their plasma membrane? A. Transport proteins B. Tight junctions C. Desmosomes D. Glycolipids
C. Desmosomes
Which of the following glycoproteins is involved with cell movement? A. Integrins B. Laminin C. Fibronectin D. Chondroitin sulfate E. Hyaluronate
C. Fibronectin
Which of the following organizations of protein structure is the most important for determining the folding of polypeptide chain? A. Secondary B. Tertiary C. Primary D. Quaternary
C. Primary
Protein structure achieved among the side chains A. Secondary structure B. Primary structure C. Tertiary structure D. Quaternary structure
C. Tertiary structure
Basal lamina contains: A. Type IV collagen B. Laminin C. both of the above D. Neither of the above
C. both of the above
Which components of extracellular matrix is considered as water loving? MACA A. Fibroblasts B. Type I collagen fibers C. proteoglycans D. Gags E. Integrins
C. proteoglycans D. Gags
Globular (functional) proteins
Compact, spherical, water-soluble, and sensitive to environmental changes Tertiary or quaternary structure (3-D) Specific functional regions (active sites) Examples: antibodies, hormones, molecular chaperones, and enzymes
Chromosomes align on the spindle equator A) Anaphase B) Telophase C) prophase D) Metaphase
D) Metaphase
Which of the following Gags are not attached to proteins. A.Chondroitin sulfate B.Keratin sulfate C.Heparan sulfate D.Hyaluronate E.All could be attached to proteins
D. Hyaluronate
Which of the following organs contains many reticular fibers? MACA A. Bone B. Cartilage C. Tendon D. Spleen E. Lymph node
D. Spleen E. Lymph node
The apical most junctions which restrict membrane protein distribution in epithelial cells are called: A. Adhesive junctions B. Desmosomes C. Gap junctions D. Tight junctions
D. Tight junctions
What is the most dominant fat in the body? A. Cholesterol B. Phospholipid C. Terpene D. Triglyceride E. Cholesterol
D. Triglyceride
Which of the following is NOT a function of the smooth endoplasmic reticulum? A. lipid metabolism and cholesterol synthesis B. steroid-based hormone synthesis C. breakdown of stored glycogen to form free glucose D. protein synthesis in conjunction with ribosomes
D. protein synthesis in conjunction with ribosomes
Nucleosome structure
DNA and histones which has a core of 8 histones
Nucleic Acids classes/types
Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)
Bonds and Interactions Are Important in Protein Folding and Stability
Disulfide bonds Hydrogen bonds
Which of the following cellular organelles contain catalases? A. Golgi complex B. lysosomes C. Smooth Endoplasmic Reticulum D. Rough endoplasmic reticulum E. Peroxisomes
E. Peroxisomes
Which of the following is a GAG? A. dermatan sulfate B. chondroitin sulfate C. keratan sulfate D. heparan sulfate E. all of the above
E. all of the above
Which of the following is a general function for a fibrous protein? A. transport B. hormones C. body defense D. catalysis E. structural framework
E. structural framework
Classes of proteins
Enzymes: function as catalysts, increasing the rates of chemical reactions Structural proteins: physical support and shape Motility proteins: contraction and movement Regulatory proteins: control and coordinate cell function Transport proteins: move substances in and out of cells
Elastic fibers
Flexible and "stretchy" fibers that add elasticity to tissue
Sarcoplasmic reticulum
Functions: --Ca2+ storage and release
Regulation of the Cycle (external)
Growth factors: 1. bind to specific receptors on cell surface 2. send cytoplasmic signals to cellular components: Examples are epidermal growth factor in skin cells, Nerve growth factor in nerve cells
Classes of proteins (continued)
Hormonal proteins - communication between cells Receptor proteins - enable cells to respond to chemical stimuli from the environment Defensive proteins - protect against disease Storage proteins - reservoirs of amino acids
Mitochondria (cellular respiration)
Inner membrane --electron transport proteins --ATP synthase enzymes Matrix --enzymes for TCA cycle and fatty acid metabolism
Axoneme
Microtubules are also organized into larger, more stable arrays
Van der Waals interaction
Molecules with nonpolar covalent bonds may have transient positively and negatively charged region (weak interaction)
Mitochondria (def)
Powerhouse of the cell, organelle that is the site of ATP (energy) production
Nucleus (Production)
Produces ribosomal subunits in nucleolus and export them into cytoplasm for assembly into ribosomes
Collagens are
Responsible for the Strength of the Extracellular Matrix most abundant ECM component in animals is a family of closely related collagens, which form fibers with high tensile strength secreted by several types of cells in connective tissues including fibroblasts
Fibrous (structural) proteins
Strandlike, water-insoluble, and stable Most have tertiary or quaternary structure (3-D) Provide mechanical support and tensile strength Examples: keratin, elastin, collagen (single most abundant protein in body), and certain contractile fibers
Rough ER
Synthesis of: --secreted proteins --membrane proteins --lysosomal proteins
Cleavage furrow
The area of the cell membrane that pinches in and eventually separates the dividing cell
what type of barrier is the basal lamina?
The basal lamina is a structural support and a permeability barrier
Primary Structure
The first level of protein structure; the specific sequence of amino acids making up a polypeptide chain.
isoprene
The five carbon units that are joined together to form Vitamin A1 and carotenoid pigments
Quaternary Structure
The fourth level of protein structure; the shape resulting from the association of two or more polypeptide subunits.
Describe the glycocalyx and its functions.
The glycocalyx is the sticky, carbohydrate-rich area on the cell surface. It helps bind cells together and provides a highly specific biological marker by which cells can recognize each other.
Terminal Bar microscopy
Using light microscopy, it appears as a bar at the apical surface of the cell, wherein the structures listed cannot be resolved. With electron microscopy, the terminal bar can be visually disseminated into these structures.
Terminal Bar
a group of junctional complexes that attach adjacent epithelial cells on their lateral surfaces: The Tight Junctions (Zonula Occludens), zonula adherens and desmosomes (macula Occludens).
Ground substance
a highly hydrated (with much bound water), transparent, complex mixture of macromolecules, principally of three classes: glycosaminoglycans (GAGs), proteoglycans, and multiadhesisive glycoproteins
Phospholipids
a lipid consisting of a glycerol bound to two fatty acids and a phosphate group.
Endomembrane system
a set of membranes that form a single functional unit as being connected directly for exchanging material through vesicular transport
Polysaccharides consist of
a single kind of repeating unit, or sometimes an alternating pattern of two kinds. Repeating units of polysaccharides are monosaccharides.
cytoskeleton function
a) cell shape and internal framework b) binding sites for organelles c) cellular movement d) cellular specializations
DNA
a)double helix - 2 complementary strands of DNA; stabilized by hydrogen bonding between bases b)chromatin -DNA packaged with histone proteins 1) heterochromatin - densely coiled, less active (2) euchromatin - less dense, transcriptionally active c)most highly condensed during mitosis - forms chromosomes
Which of the following contain axoneme? (MACA) a. Cilia b. Centrioles c. Flagella d. stereocilia
a. Cilia c. flagella
Disulfide is what kind of bonding? a. Covalent bond b. Ionic Bond c. Hydrogen bond d. None of the above
a. Covalent bond
Which molecule maintains long term storage of genetic information? a. DNA b. mRNA c. rRNA d. tRNA
a. DNA
Which of the following structures are made of Microtubules? MACA a. Flagella b. Actin c. Intermediate filament d. axoneme
a. Flagella d. axoneme
Which of the following organelles is/are responsible for completion of glycosylation of glycoproteins a. Golgi complex b. rough endoplasmic reticulum c. smooth endoplasmic reticulum d. mitochondria
a. Golgi complex
Actin filaments are involved in: (MACA) a. Muscle contraction b. cleavage furrow formation c. Cytoplasmic streaming d. Mitotic Spindle
a. Muscle contraction b. cleavage furrow formation c. Cytoplasmic streaming
Fibronectin function
a. binds cells to components of extracellular matrix b. binding site for cells, collagen, heparan
Which of the following macromolecules is a polysaccharide used for structure? a. cellulose b. starch c. glucose d. glycogen
a. cellulose
Prophase
a. chromatin condenses - chromosomes become visible b. nuclear envelope breaks down c. centrosomes (pair of centrioles) separate to opposite poles d. microtubules generated connecting centrioles to chromosomes
metaphase
a. chromosomes condense further and attach to the mitotic spindle at large electron-dense protein complexes called kinetochores at each centromere b. Chromosomes are moved to align at its equatorial plane
Collagen fibers (ECM)
a. family of 25+ proteins b. Synthesis as procollagen; soluble; triple helix of 3 polypeptides c. after secreted converted tropocollagen; insoluble d. self-assembles to form fibrils and fibers
Which of the following statements regarding macromolecules is false? MACA a. it always involves polymerization of individual monomeric units b. it requires a net input of energy c. there is no directionality to the biosynthetic process d. molecules are joined together via hydration reactions
a. it always involves polymerization of individual monomeric units c. there is no directionality to the biosynthetic process d. molecules are joined together via hydration reactions
Which organelle has a highly acidic interior containing many hydrolytic enzymes? a. lysosome b. nucleus c. peroxisome d. smooth ER
a. lysosome
telophase
a. nuclear envelope regenerated b. chromosomes disperse
Laminin
a. synthesized by epithelial cells b. binds epithelia to components of basal lamina c. binding sites for collagen, heparan, cells
Steroid Hormones types
estradiol (estrogen) testosterone (anderogen) cortisol (glucocorticoid) aldosterone (mineralococorticoid)
Reticular
a. very thin fibers form loose networks b. high affinity for silver stains; argyrophilic c. found in lymphoid organs, ie. lymph nodes, spleen 3. elastic a. fiber bundles composed of elastin b. cross-linked peptides provide extensibility
Microfilaments composition
actin (1) G-actin - unpolymerized globular actin proteins (2) F-actin - filamentous actin formed by polymerization of G-actin
Centrosome
aka MTOC: Microtubule organization center for the mitotic spindle and consists of paired centrioles.
tight junction function
aka Zonula Occludens (ZO) --prevent water soluble molecules from passing through extracellular matrix between cells --fuse adjacent plasma membranes --protein strands in adjacent membranes fuse them together -maintains the polarity of the cell by restricting membrane proteins to the apical or baso/lateral surfaces --disrupted by reduction of calcium concentration
triglycerides
aka triacylglycerols consist of a glycerol molecule with three fatty acids attached to it most common in body
gap junction
allows the passage of small water-soluble molecules from cell to cell
Plasma membrane proteins are
amphipathic
Actin-linked cell-matrix junction
anchors actin filaments in cell to extracellular matrix
hemidesmosomes
anchors intermediate filaments in a cell to extracellular matrix
Reticular (type III collagen) fibers
argyrophilic
Extrinsic (peripheral) proteins
associated with either cytoplasmic or extracellular region of membrane
Peroxisomes: MACA a. Also named lysosomes b. Contain oxidases c. Contain acid phosphatases d. Breakdown long chain fatty acids
b. Contain oxidases d. Breakdown long chain fatty acids
Golgi apparatus contains ribosomes within its cisternae? a. True b. False
b. False
The site of steroid synthesis is: a. RER b. SER c. Golgi complex d. Peroxisomes
b. SER
Which of the following statements regarding macromolecules is true? a. it always involves polymerization of individual monomeric units b. it requires a net input of energy c. there is no directionality to the biosynthetic process d. molecules are joined together via hydration reactions
b. it requires a net input of energy
Which of the following cellular organelles contain hydrolytic enzymes? a. Golgi complex b. lysosomes c. Smooth Endoplasmic Reticulum d. Rough endoplasmic reticulum e. Peroxisomes
b. lysosomes
triglycerides are made of? a. two fatty acids and one glycerol molecule b. three fatty acids and one glycerol molecule c. two fatty acids plus one glycerol and one phosphate group d. none of the above
b. three fatty acids and one glycerol molecule
Adhesive glycoproteins
bind membrane proteins to collagen fibers 2 types: fibronectin & laminin
Lipids
biochemically, structurally diverse hydrophobic stable in nonpolar solvents mostly hydrocarbon chains (containing C and H) some have polar regions-amphipathic
If the nucleotide or base sequence of the DNA strand used as a template for messenger RNA synthesis is ACGTT, then what would be the sequence of bases in the corresponding mRNA? a. TGCAA b. ACGTT c. UGCAA d. GUACC
c. UGCAA
Proteins are made by polymerization of ________ a. fatty acids b. monosaccharides c. amino acids d. nucleotides
c. amino acids
Cytosine is found in? a. DNA only b. RNA only c. both DNA and RNA d. neither DNA nor RNA
c. both DNA and RNA
All of the following are examples of biological macromolecules Except: a. cellulose b. Starch c. glucose d. Hemoglobin
c. glucose
Proteins are formed by polymerization of amino acids joined together by ___________ bonds. a. glyosidic b. ionic c. peptide d. None of the above
c. peptide
Which of the following nitrogenous bases is not present in RNA? a. adenine b. cytosine c. thymine d. uracil
c. thymine
Protein Primary Structure
can be used to predict higher level protein structure
Glycolipids
carbohydrates covalently bonded to lipids determine type of cell, important for immune system
amino acids made of:
carbon atom (Chiral center) bonded to hydrogen atom amine (or amino group) variable side chain (R)
Mitosis
cell division in which the nucleus divides into nuclei containing the same number of chromosomes relatively uniform in length; 1-2 hours
Gap Junctions (Nexus)
communicating junctions --allows passage of ions and small molecules between adjacent cells --cells connected by connexons -six subunits composed of protein connexins --important in cardiac and smooth muscle allowing multiple cells to act as a single unit
Fatty acids are
components of several other kinds of lipids long amphipathic, unbranched hydrocarbon chain with a carboxyl group at one end The polar carboxyl group is the "head" and the nonpolar hydrocarbon chain is the "tail"
cytoskeleton structure
composed of 3 types of proteinaceous structures: a) microtubules b) microfilaments c) intermediate filaments
centrioles structure
composed of 9 triplets crosslinked to each other most cells have 1 pair of centrioles
Proteins are
composed of a nonrandom series of amino acids
adherenes junction
connects actin filament bundle in one cell with that in the next cell
desmosome
connects intermediate filament in one cell to those in the next cell
amino acids linked by
covalent called Peptide bond (formed between amine group of one amino acid and carboxyl group of next amino acid.
Which of the following structures does not connect the membranes of two neighboring cells? a. gap junctions b. tight junctions c. desmosomes d. Hemidesmosomes
d. Hemidesmosomes
Microtubules are not found in: a. axoneme b. stereocilia c. flagellum d. centrioles
d. centrioles
All of the following cellular structures contain microtubules except: a. cilia b. stereocilia c. flagella d. mitotic spindle
d. mitotic spindle
Apoptosis
def. = programmed cell death --kills old, damaged, infected, unneeded or otherwise abnormal cells --cells shrink, detach, round-up --release chemoattractants to stimulate phagocytosis --occurs during development --no inflammation
Cytokinesis
division of the cytoplasm A belt-like contractile ring of actin filaments forms at the end of anaphase, constriction of this ring produces a cleavage furrow and progresses until the cytoplasm and its organelles are divided into two daughter cells, each with one nucleus.
Polysaccharides function
energy storage and structural support most common energy storage form is starch (in plant cells) and glycogen (animal cells and bacteria) best-known structural polysaccharide is the cellulose found in plant cell walls --Mammals cannot digest cellulose (some have microorganisms in their digestive systems that can)
Classes of lipids
fatty acids triglycerides phospholipids glycolipids steroids Terpenes
Chromatin packing
folding and coiling DNA with the help of proteins
Ionic bonds
form between positively and negatively charged R groups
Disulfide bonds
form between the sulfur atoms of two cysteine residues (covalent bond)
Hydrogen bonds
form in water and between amino acids in a polypeptide chain via their R groups
Terpenes
formed from isoprene synthesized from the five-carbon compound isoprene and are sometimes called isoprenoids
Cilia and Flagella
hairlike structures that extend from the surface of the cell, where they assist in movement
Nucleus (Cellular regulation)
houses genetic materials, which directs all cellular activities and regulates cellular structure
Phases of the cell cycle in order
interphase (G1 = growth, S = growth and DNA synthesis, G2 = growth and final prep. for division), prophase, metaphase, anaphase, telophase, cytokinesis
microtubules structure
largest cytoskeletal elements (1) tubulin A. globular proteins B. a and b tubulin form heterodimers (2) assembly of heterodimers into protofilaments 3) protofilaments form hollow tube-like structure 4) microtubules may form as singlets, doublets, or triplets
Polysaccharides are
long chain polymers of sugars and sugar derivatives that are not informational molecules aka complex carbohydrates
Stereocilia
long tufts on top of hair cells that sway back and forth causing the opening of ion channels Hair cells are connected to the tectorial membrane and the hair cells are involved in amplifying the incoming sound
Structure of cilia and flagella
made up of two different parts: the motile cilium (upper part) and basal body (lower part ) organized into 9 pairs of microtubules with two microtubules at the center of the ring
Cholesterol
most common --Found in membrane --Regulates membrane fluidity --Involved in cellular signaling --Source of all steroid hormone
Karyokinesis (mitosis)
nuclear division
Cell Cycle
orderly progression of events in life of a cell
Interphase
period of the cell cycle between cell divisions 1. all other cellular events 2. variable in length in different cell types
terpenes can be found in
primary constituents of the essential oils of many types of plants and flowers. Essential oils are used widely as fragrances in perfumery and traditional medicine, such as aromatherapy
multimeric proteins
protein with 2 or more polypeptide chain two polypeptides are called dimers or three polypeptides are called trimers Hemoglobin is a tetramer, consisting of two alpha subunits and two beta subunits
monomeric proteins
proteins that consist of a single polypeptide
Cell cortex
reinforcing mesh of cytoskeletal elements under a plasma membrane
Macromolecules are
responsible for most of the form and order of living systems are generated by the polymerization of small organic molecules
Tight junctions
seals gap between epithelial cells
Desmosomes (Macula adherens)
similar to zonula adherens -disc shaped -cytoplasmic intermediate filaments anchor the cadherin membrane proteins (desmoglein and desmocollin) that bind the cells. It strengthens the tissue.
anaphase
sister chromatids separates and move toward the opposite pole
Ribosomes
site of protein synthesis
Nucleolus function
site of synthesis and organization of ribosomes (structures used in protein synthesis)
Cell Junctions are
specialized attachments between adjacent cells --modifications of the plasma membrane --to provide anchoring of adjacent cells to one another --to provide cytoplasmic continuity between cells
Hydrophobic interaction
the tendency of hydrophobic molecules or parts of molecules to be excluded from interactions with water
nucleic acids importance
they store, transmit, and express genetic information
Glycerol
three-carbon alcohol with a hydroxyl group on each carbon Note: Fatty acids are linked to glycerol, one at a time, by ester bonds, formed by the removal of water
Tertiary Structure def.
three-dimensional shape of a polypeptide due to interactions of the R groups of the amino acids making up the chain.
necrosis
tissue death --increase in cell volume (inflammation) --loss of plasma membrane integrity --leakage of cellular contents
Motifs are
units of secondary structure consist of short stretches of a helices and b sheets OR Certain combinations of alpha helices and beta sheets have been identified in many proteins eg. b-a-b, the hairpin loop, and the helix-turn-helix motifs
Surface Specialization Microvilli
~1μm long 1. covered with glycocalyx (sugar residues linked to membrane lipids and proteins 2. form brush (striated) border 3. found extensively on apical surfaces of absorptive cells 4. core of actin filaments arranged longitudinally 5. not motile
Fibronectin structure
•Each fibronectin subunit is folded into a series of rodlike domains •Several domains bind one or more ECM macromolecules, including several types of collagen, heparin, and fibrin •Other domains recognize and bind cell surface receptors via the RGD (arg-gly-asp) sequence
Integrins Are Cell Surface Receptors That Bind ECM Constituents
•Integrins are a large family of cell surface receptors that bind to fibronectins or laminins and collagen •Integrins integrate the cytoskeleton with the ECM •Integrins play important roles in regulating cell movement and attachment
Laminins Bind Cells to the Basal Lamina
•Laminins are found mainly in the basal lamina, a thin sheet of specialized extracellular material •It underlies epithelial cells, separating them from connective tissues
Fibronectin is involved in cell movement
•When migratory cells are grown on fibronectin, they adhere to it •In embryonic cell migration, the pathways followed by migrating cells are rich in fibronectin, suggesting it may guide the cells •Many kinds of cancer cells do not produce fibronectin