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138 Cards in this Set

  • Front
  • Back
Basic living and structural unit of the body.
Cell
What are the 3 principal parts of a cell?
Plasma membrane, cytoplasm (organelles + cytosol), and nucleus.
Why is the plasma membrane best described using the fluid mosaic model?
The membrane consists of proteins that float like icebergs in a sea of lipids. Many of the lipids and proteins are free to rotate and move sideways in their own half of the bilayer.
What 3 lipid molecules make up the lipid bilayer? Give their ratio %.
75% phospholipids, 20% cholesterol, 5% glycolipids
How do hydrophobic and hydrophilic regions govern the arrangement of the lipid bilayer?
The hydrophilic phosphate head faces the water and the hydrophobic fatty acid tails face eachother away from the water.
How does cholesterol affect membrane fluidity?
Because of the way it forms H bonds w/ phospholipid and glycolipid heads and fills space b/w bent fatty acid tails, cholesterol makes the lipid bilayer stronger but less fluid at normal body temperature. At low temps, cholesterol increases membrane fluidity.
What substances can and cannot diffuse through the lipid bilayer?
Permeable to nonpolar, uncharged molecules like oxygen, carbon dioxide, steroids. Slightly permeable to water and urea. Impermeable to ions and large, uncharged polar molecules like glucose.
___ proteins extend into or through the lipid bilayer and are firmly embedded.
Integral proteins
Most integral proteins are ___ proteins that extend into or through the lipid bilayer.
Transmembrane proteins
___ proteins attach to the inner/outer surface of the membrane.
Peripheral proteins
A sugary coat made up of the carbohydrates of glycoproteins and glycolipids. Acts as a molecular signature.
Glycocalyx
Name the 6 types of membrane protein functions.
Ion channel, carrier (transporter), receptor, enzyme, linker, cell ID marker.
Membrane protein that allows specific ions to move through water-filled pore.
Ion channel
Membrane protein that transports specific substances across the membrane by changing shape.
Carrier (transport)
Membrane protein that recognizes specific ligand and alters cell's function in some way.
Receptor
Membrane protein that catalyzes reaction inside/outside cell.
Enzyme
Membrane protein that anchors filaments inside and outside the plasma membrane, providing stability and shape for the cell.
Linker
Membrane protein that distinguishes your cells from anyone else's.
Cell identity marker
The property of membranes allowing some substances to pass more readily than others is called ___. Supports the existence of concentration gradients.
Selective permeability
Difference in amount of solute from one place to another.
Concentration gradient
Difference in electrical charges in 2 regions is called ___. On the plasma membrane it is called ___.
Electrical gradient. Membrane potential.
Combined influence of concentration gradient + chemical gradient of ion is called ___.
Electrochemical gradient
What is the ratio of water volume in the body that makes up the cytosol (ICF)?
2/3 ICF (1/3 ECF)
How do substances move along their concentration gradient in a passive process vs. active process? Is energy required?
Passive - substance moves down gradient using its own kinetic energy. Active - substance moves "uphill" against gradient using cellular energy (ATP).
Passive process in which random mixing of particles in a solution occur because of the particles' kinetic energy.
Diffusion
5 factors that influence the rate of diffusion of substances across plasma membranes.
Steepness of concentration gradient, temperature, mass of diffusing substance, surface area, diffusing distance
The hormone insulin binding to a protein is best represented by which membrane protein function?
Receptor
How would a fever affect body processes that involve diffusion?
Because fever increases body temperature, the rates of all diffusion processes would increase.
What types of molecules move across the plasma membrane via simple diffusion?
Oxygen, carbon dioxide, nitrogen gases, fatty acids, steroids, fat-soluble vitamins (ADEK). Water, urea, small alcohols.
Passive process in which substances move freely through lipid bilayer without help of membrane transport proteins.
Simple diffusion
Passive process where solutes that are too polar or highly charged move through lipid bilayer with assistance of integral membrane protein.
Facilitated diffusion
The number of carriers available in a plasma membrane is called the ___, the rate at which facilitated diffusion can occur.
Transport maximum
List 2 types of facilitated diffusion processes in the cell membrane.
Channel-mediated and carrier-mediated facilitated diffusion.
Is the concentration of K+ in body cells higher in the cytosol or the ECF?
K+ concentration is higher in the cytosol.
How does insulin alter glucose transport by facilitated diffusion?
Promotes copies of glucose carriers into the plasma membrane. Insulin elevates the transport maximum for glucose into cells. With more glucose carriers available, cells can pick up glucose more rapidly.
Net movement of water through selectively permeable membrane from high water concentration (low solute) to low water concentration (high solute).
Osmosis
What 2 ways can water pass through the plasma membrane?
Simple diffusion and aquaporins (integral membrane protein that functions as water channel)
Pressure exerted by a liquid.
Hydrostatic pressure
Measure of solution's ability to change volume of cells by altering water content.
Tonicity
How does a cell's shape change in an isotonic solution? Give an example of an isotonic solution.
Shape is maintained b/c there is no net water movement into or out of the cell. Ex. 0.9% NaCl
What is a hypotonic solution and how do RBCs change shape? Give an example of a hypotonic solution.
Solution that has a lower concentration of solutes outside of cell. Water enters cell and causes hemolysis (lysis). Ex. Pure water, sports drinks.
What is a hypertonic solution and how do RBCs change shape? Give an example of a hypertonic solution.
Solution that has a higher concentration of solutes outside of cell. Water leaves cell and causes crenation. Ex. 2% NaCl
What is the main difference b/w primary active transport and secondary active transport?
Primary - uses energy from hydrolysis of ATP. Secondary - uses stored energy from Na+/H+ concentration gradient.
What solutes are transported across the plasma membrane using primary active transport?
Na+, K+, H+, Ca2+, I-, Cl-
Most prevalent primary active transport pump.
Sodium-potassium pump (Na+/K+ATPase)
Describe 2 reasons why the different concentrations of Na+ and K+ in cytosol and ECF are important.
Crucial for maintaining cell volume and ability for some cells to generate electrical signals (action potentials).
Transporter that moves substances in the same direction.
Symporter
Transporter that moves substances in different directions.
Antiporter
Process of materials moving into a cell in a vesicle formed from plasma membrane.
Endocytosis
Process of materials moving out of a cell by fusion w/ plasma membrane of vesicles formed inside cell.
Exocytosis
Process of cells taking up specific ligands which trigger infolding of clathrin-coated pit that forms vesicle.
Receptor-mediated endocytosis
What disease can be treated with a hypertonic solution?
Cerebral edema b/c of excess interstitial fluid in brain.
Why is digitalis given to patients with heart failure?
It slows sodium-potassium pump which causes more Ca2+ to remain in heart muscle cells and strengthens heart contractions. P73
What virus uses receptor-mediated endocytosis to enter and infect body cells?
HIV which causes AIDS
What ligands are transported with receptor-mediated endocytosis?
Iron, vitamins, hormones, antibodies, low-density lipoproteins (LDLs)
"Cell eating"; movement of solid particle into a cell after pseudopods engulf it to form a phagosome.
Phagocytosis
"Cell drinking"; movement of ECF into a cell by infolding of plasma membrane to form a vesicle. Largely found in intestines/kidneys.
Bulk-phase endocytosis or Pinocytosis
Phagocytosis helps protect body from disease. What 3 types of substances are engulfed?
Bacteria, viruses, aged/dead cells
2 important cells that carry out exocytosis.
Secretory cells (enzymes, hormones, mucus) and nerve cells that release neurotransmitters.
Process of vesicle transport to move substance into, across, and out of cell.
Transcytosis
What are some of the chemicals present in cytosol?
Ions, glucose, amino acids, fatty acids, protein, lipids, ATP, waste products.
What is the function of cytosol?
Site of many chemical reactions needed for cell's survival.
Fluid portion of cytoplasm that surrounds organelles and makes up 2/3 of water volume in body.
Cytosol (ICF)
Structures w/ characteristic shape and specialized function.
Organelle
Network of protein filaments that extend throughout cytoplasm, providing cellular shape, organization and movement.
Cytoskeleton
What protein filament is made of actin, is part of the framework of a cell and composes microvilli and cell junctions?
Microfilament
What protein filament is made of keratin, provides internal support for cells, and composes cell junctions, skin, keratinocytes?
Intermediate filament
What protein filament is made of tubulin, is found in the centrosome and aids in the mitotic spindle, cila and flagella?
Microtubule
Located near nucleus. Consists of pericentriolar material and pair of centrioles. Organizing center of growth for mitotic spindle.
Centrosome
What is the function of pericentriolar material in dividing vs. nondividing cells?
Dividing - mitotic spindle. Nondividing - organizes microtubules
Short, hair-like projections from cell surface that move fluids along cell surface.
Cilia
Hair-like projections on cell surface that are longer than cilia and move an entire cell.
Flagella
Consist of 2 subunits made in the nucleus. Site of protein synthesis
Ribosome
Where are subunits of ribosomes synthesized and assembled?
Synthesized in nucleolus, assembled in cytoplasm.
Functions in synthesizing fatty acids + steroids, helping liver cells release glucose into bloodstream and detoxification.
Smooth ER
Contain ribosomes that synthesize protein. Processes and sorts proteins that enter. Produces secretory proteins, membrane proteins, organelle proteins; forms glycoproteins; synthesizes phospholipids; attaches proteins to phospholipids.
Rough ER
Small flattened membranous sacs with bulging edges in Golgi Complex
Cisternae
Convex entry of Golgi complex that faces rough ER
Cis face
Concave exit of Golgi complex that faces plasma membrane
Trans face
Modifies, sorts, packages and transports molecules synthesized in rough ER in vesicles.
Golgi complex
Membrane enclosed vesicles formed in Golgi complex that contain strong hydrolytic and digestive enzymes. Carries out autophagy, autolysis, and extracellular digestion.
Lysosomes
Process where entire worn-out organelles are digested.
Autophagy (self-eating)
Process where lysosomal enzymes destroy entire cell containing them.
Autolysis (self-break apart)
Oxidizes amino acids, fatty acids, toxic substances (alcohol). Abundant in liver.
Peroxisomes
Organelle that destroys unneeded, damaged or faulty proteins into small peptides.
Proteasomes
Organelle that generates ATP. Consist of smooth outer membrane, inner membrane containing cristae, and cavity called matrix. Self replicating.
Mitochondria
How do the cristae of a mitochondrion contribute to its ATP producing function?
Increase the surface area available for chemical reactions and contain enzymes needed for ATP production.
In what cells would you find abundant mitochondria?
Active cells like muscles, liver, kidneys
Double membrane that separates nucleus from cytoplasm.
Nuclear envelope
Openings in nuclear envelope that control movement of substances b/w nucleus and cytoplasm.
Nuclear pores
Spherical body that produces ribosomes
Nucleolus
Cell's heredity units, control activities and structure of cell.
Genes
Long molecules of DNA combined w/ protein molecules
Chromosomes
Complex of DNA, proteins, some RNA called ___. Total genetic info carried in a cell is its ___.
Chromatin. Genome.
How many chromosomes do human somatic cells have and how many are inherited from each parent?
46 chromosomes. 23 inherited from each parent.
What are the components of a nucleosome?
Double-stranded DNA wrapped twice around 8 proteins called histones.
Describe 2 reasons proteins are important to the life of a cell.
Determine physical and chemical characteristics of cells.
All of an organism's proteins is called ___.
Proteome
A sequence of 3 nucleotides in DNA is called ___.
Base triplet
Set of rules that relates base triplet sequences of DNA to corresponding codons of RNA and amino acids they specify.
Genetic code
Where do transcription and translation occur?
Transcription occurs in nucleus; translation occurs in cytoplasm.
Regions within a gene that do not code for parts of protein are called ___. They are located b/w regions that do code for segments of a protein called ___.
Introns. Exons.
Describe the process of transcription (RNA/DNA).
DNA unzips and uncoils. Enzyme RNA polymerase catalyzes transcription of DNA. Bases ATGC are paired but U replaced with T in RNA. Pre-mRNA strand is edited by enzyme snRNPs that remove introns and splice together exons. mRNA leaves nucleus.
Describe the process of translation (RNA/DNA).
mRNA binds to small ribosomal unit. tRNA anticodon + amino acid binds to mRNA start codon (AUG). Large ribo unit attaches to small ribo unit and initiator tRNA fits into P site. 2nd anticodon + amino acid fits into A site. Peptide bond forms b/w amino acids. tRNA in P site detaches, tRNA in A site w/ peptide chain shifts to P site. Repeats until stop codon reached at A site. Completed protein detaches from tRNA and ribosome splits into large/small units.
Any cell of the body other than a germ cell.
Somatic cell (soma=body)
Gamete (sperm or oocyte) or precursor cell
Germ cell
___ cell division replaces or adds new ones and involves ___ and ___.
Somatic. Mitosis. Cytokinesis.
___ cell division results in gametes and consists of ___ and ___.
Reproductive. Meiosis. Cytokinesis.
2 chromosomes that make up each pair are called ___ ___.
Homologous chromosomes (homologs)
Somatic cells contain 2 sets of chromosomes and are called ___ cells.
Diploid
In chromatin's structure, each bead is called a ___ and consists of double-stranded DNA wrapped twice around a core of 8 proteins called ___.
Nucleosome. Histones.
A pair of ___ make up a chromosome.
Chromatids
Which type of RNA directs the synthesis of a protein?
mRNA
Which type of RNA joins with ribosomal proteins to make ribosomes?
rRNA
What enzyme catalyzes transcription of DNA?
RNA polymerase
What is the significance of a polyribosome?
It is several ribosomes attached to the same mRNA which allows the translation of 1 mRNA into several identical proteins at the same time.
Study of relationships b/w the genome and biological functions of an organism.
Genomics
In which phase of the cell cycle does the following occur: organelle/cytosolic components replication, centrosome replication.
Growth 1 phase (G1)
In which phase of the cell cycle does replication of DNA and centrosomes occur?
Synthesis phase (S)
In which phase of the cell cycle does replication of centrosomes complete, cell growth, enzyme/protein synthesis continue?
Growth 2 phase (G2)
Chromatin condenses into chromosomes; nuclear envelope disappears; centrosomes move to opposite ends as mitotic spindle lengthens
Prophase
Chromosomes line up at metaphase plate.
Metaphase
Chromosomes split and identical sets move to opposite sides of cell.
Anaphase
Nuclear envelope reappears. Chromosomes resume chromatin form. Mitotic spindle disappears.
Telophase
Cytoplasmic division; cleavage furrow forms and divides cell
Cytokinesis
What are the 5 steps of the cell cycle in somatic cell division?
G1, S phase, G2, Mitosis, Cytokinesis
Genetically programmed death of a cell
Apoptosis
Pathological cell death from tissue injury
Necrosis
What accounts for the genetic variation among organisms?
Crossing-over results in genetic recombination
How is anaphase 1 of meiosis different from anaphase of mitosis?
During anaphase 1 of meiosis, the chromosome does not separate. In mitosis, the chromosome splits into chromatids.
Why are sperm cells the only body cells that need to have a flagellum?
They are the only cell that need to move a long distance.
Branch of medecine that deals with medical problems and care of elderly.
Geriatrics
Study of process and problems associated w/ aging.
Gerontology
Out of the 4 types of tissues, which divide and which do not?
Epithelial, connective DIVIDE. Nervous, skeletal muscle DO NOT.
What is the one reason some tissues become stiffer as they age?
Glucose forms irreversible cross links b/w adjacent protein molecules.
Disease characterized by normal development in 1st year followed by rapid aging. Telomeres are short.
Progeria
Rapid acceleration of aging in 20's
Werner syndrome
Spread of cancerous cells to other parts of the body.
Metastasis