Exam 1 Flashcards
(138 cards)
1
Q
Anatomy:
Physiology:
A
Anatomy:the study of the structure of the body parts &their relationship to one another
Physiology:the study of the function of the body’s structural machinery
2
Q
Gross anatomy:
A
The study of large body structures (heart,lungs, kidneys)
3
Q
Microanatomy:
A
The study of microscopic body structures; CYTOLOGY is the study of cells and HISTOLOGY is the study of tissues
4
Q
Regional anatomy:
A
The study of groups of structures in specific body regions
5
Q
Systematic anatomy
A
The gross anatomy of organ systems is studied
6
Q
Surface anatomy
A
The study of internal body structures as they relate to the body surface (skin)
7
Q
Developmental anatomy
A
The study of structural body changes that occur throughout the life span; EMBRYOLOGY studies developmental changes that occur before birth
8
Q
Renal physiology:
Neurophysiology:
A
Renal physiology: the study of kidney function
Neurophysiology: the study of the nervous system
9
Q
Levels of structural organization in organisms
Chemical level:
A
-Atoms/elements(carbon,hydrogen,oxygen,sodium)
-Molecules/compounds(sugar,salt,water)
-Macromolecules(proteins,lipids, carbohydrates, nucleic acids)
-Organelles(mitochondrion, nucleus, plasma membrane
10
Q
Levels of structural organization in organisms
Cellular level:
A
-Molecules, macromolecules and organelles combine to form cells
-Whole greater than sum of its parts
-cells:basic structural and functional units of organisms
11
Q
Levels of structural organization in organisms
Tissue level:
A
-cells combine to form tissue
-TISSUE: a group of cells & surrounding structures that together -reform a specific function
- 4 basic tissue types: e-ithelial tissue, connective tissue, muscle tissue, nervous tissue
12
Q
Level of structural organization in organisms
Organ level: different kinds of tissue combine to form organs
A
-Organ: a group of 2 or more different tissue that together perform a specific function
-exam-les of organs: stomach, heart, liver, lungs, and brain
13
Q
Level of structural organization In organisms
Organ system level: a group of organs that together form an organ system
A
-Organ systems in the body: integumentary system; skeletal system; muscular system; immune system; respiratory system; nervous system; endocrine system; cardiovascular system; lymphatic system; digestive system; urinary system; reproductive system; respiratory system
14
Q
Levels of structural organization in organisms
Organismal level:
A
The whole organism; all parts of the body functioning together
15
Q
Necessary life functions
A
Metabolism: all the chemical reactions that occur in body cells
-catabolism:breakdown of complex molecules into simpler ones
-anabolism:buildup of complex molecules from simpler ones
Responsiveness:the ability to sense environmental changes (stimuli) and respond accordingly
Movement:body movement is carried out by the muscular system; muscle cells have contractility-the ability to move by shortening
Growth:increase body size resulting from increase in cell size and or number
Differentiation:process during which a cell changes from an unspecialized state to a specialized state to suit its function
Reproduction:cellular and organismal
16
Q
Autopsy:
A
Postmortem (after death) examination of the body and dissection of internal organs to confirm or determine cause of death
17
Q
Survival needs:
A
Nutrients-for energy, structural support, cellular reactions
Oxygen-for cellular respiration (energy)
Water-many functions
Normal body temperature(98f or 37c)-maintains normal reaction rate
Normal atmospheric pressure-for proper breathing
18
Q
Homeostasis
A
The maintenance of internal conditions within normal limits
19
Q
Homeostatic control mechanism
A
Receptors sense changes or stimuli in the environment and send information along an afferent pathway to a control center (central nervous system). The control center determines the appropriate response and sends information along a efferent pathway to an effector (muscle,gland) that effects the response
20
Q
Negative feedback:
A
The product or response shuts off or reduces the level of original stimulus; the variable then changes in a direction opposite the initial change
Ex; regulation of body temp.
21
Q
Positive feedback:
A
The product or response enhances or exaggerates the original stimulus such that the response is continued
Ex;blood clotting
22
Q
Homeostatic imbalance
A
Some lack of ability to activate or carry out control mechanisms-Age is one factor
23
Q
Body fluids
A
Intracellular fluids(ICF)- fluid within the cell
Extracellular(ECF)- fluid outside the cell
-interstitial fluid:fills narrow spaces between cells of tissues
-Also blood -lawmakers,lymph,cerebrospinal fluid, synovial fluid…
24
Q
Serous membrane
A
Thin 2 layer membranes with fluid filled space that covers the viscera within thoracic and abdominal cavities and ounces walls of thorax and abdomen
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2 layers of the serous membrane
Visceral layer: covers and adheres to organs within cavity
Parietal layer:lines wall of cavity
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-pleura:
Covers lungs within pleural cavity
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Pericardium
Covers heart within pericardial cavity
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Peritoneum
Covers abdominal viscera within abdominal cavity
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Anatomical position
Standing straight, facing forward with feet slightly apart, arms at sides and palms of the hands facing forward
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Orientation and directional terms
Superior (cephalon or cranial)- toward the head or upper part of structure
Inferior (caudal)-away from head or lower part of structure
Anterior-front of the body
Posterior-back of the body
Medial-closer to the midline
Lateral-further from midline
Intermediate-between 2 structures
Proximal-nearer trunk of the body, origin or point of attachment(usually limbs)
Distal-further from trunk of body, origin or point of attachment (usually limbs)
Superficial-toward or at surface of body
Deep-away from surface of body
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Planes of the body
-Sagittal plane:vertical plane that divides body organ into left and right parts
-midsaggital- divides into equal left and right part
-parasaggital-divides into unequal left and right parts
-Frontal plane-divides body into anterior and posterior parts
-Transverse plane: divides body into superior and inferior parts
-oblique planes- passes through body or organ at angle between transverse plane and sagittal or frontal plane
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Dorsal body cavity
-cranial cavity
-vertebral or spinal cavity
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Ventral body cavity
-Thoracic cavity
-pleural cavity
-mediastinum
-pericardial cavity
-Abdominopelvic cavity
-abdominal cavity
-pelvic cavity
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Abdominopelvic regions
-right hypochondriac region;epigastric region;left hypochondriac region
-right lumbar region; umbilical region; left lumbar region
Right iliac(inguinal) region; hypogastric region; left iliac region
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Abdominopelvic quadrants
-right upper;left upper quadrant
-Right lower; left lower quadrant
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Basic chemistry
Matter:anything that has mass and takes up space
-matter is composed of elements
-states of matter:solid,liquid or gas
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Elements:are composed of atoms
Atoms:are composed of subatomic particles
-protons (+ charge)
-neutrons (no charge)
-electrons(-charge)
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The atomic numeric of an atom=the number of protons in its nucleus
-the periodic table is grouped according to atomic number (hydrogen has an atomic number of 1)
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The atomic mass (mass number)
The atomic mass of an atom is the number of protons+ number of neurons in its nucleus
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The atomic weight
The atomic weight of an elements is the average of the relative weights of all the isotopes of that element
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Isotopes
Isotopes are atoms of an element that have the same number of protons(atomic number) but different mass numbers )different number of neurons
-radioisotopes are unstable isotopes that spontaneously decay into more stable forms
-Radioactivity can be detected with scanning devices and radioisotopes can be incorporated into biological molecules
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96% mass of a person
Carbon, hydrogen,oxygen and nitrogen
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Molecules
2 or more atoms held together by chemical bonds
-when 2 or more atoms of the same element bind, the form a molecule of that element
-when 2 or more different atoms bond, they form one molecule of a compound
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Chemical bonds
Electrons of an atom differ in amount of potential energy
-electrons closest to the nucleus have then;east potential energy
-electrons farthest from the nucleus have the greatest potential energy(valance or bonding electrons)
First energy level can contain a maximum of 2 bonding electrons
Second energy level can contain 8 bonding electrons
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Bonding:
Ionic bonding
Ionic bonding: transfer of electrons from one atom to another
-results in ions:charged particles resulting from charge imbalance (greater or fewer electrons than protons) due to electron transfer
-ex:NaCl
-chemical formulas of compounds based on # of valence electrons (ex: MgCl2,mg has has 2 valence electrons to donate, while cl can only accept 1, so two cl atoms are needed to accept the 2 valence electrons donated by one mg atom)
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Bonding:
Covalent bonding
Covalent bonding:sharing of electrons between 2 or more atoms
-each atom acquires an octet of valence electrons( electrons in outermost shell). Ex:CH4,O2
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Bonding:
Polar covalent bond
Polar covalent bond:unequal sharing of electrons between atoms in a covalent bond (water,h2o)
-due to difference in electronegative of atoms in bonds
-more electronegative atom has slight negative charge, less electronegative atom has slight positive charge
-Asymmetrical differences lead to polar molecules
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Bonding:
Hydrogen bonding
Hydrogen bonds:
-bonding between a slightly positive hydrogen atom of one molecule, and a slightly negative atom(usually oxygen or nitrogen) of the same or another molecule
-weak bonding compared to ionic and covalent bonding. But many bonds increase strength
-good example is water molecule
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Energy
Energy- the capacity to do work
-potential energy:stored energy that is available to do work
-kinetic energy:energy of motion
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Forms of energy
Chemical energy:energy in he bonds of chemicals
-ATP (adenosine triphosphate) has chemical energy and is the form of energy used by all reactions in cells
Electrical energy-energy in he movement of charged particles
Mechanical energy-energy used directly to move matter(muscle cells use mechanical energy)
Radiant energy-energy that travels in waves (including solar energy, light energy)
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Exergonic reactions:
Endergonic reactions:
Exergonic reactions:release energy
Endergonic reactions:require (absorb) energy
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The rate of a chemical reaction is influenced by:
1.temperature:molecules move faster as the temp is increased(increases collisions)… moderate temp is best; high temps often denature (inactive) enzymes
2.particle size: small molecules move faster (more forceful collisions)
3.concentration:usually increased reactant concentrations increases rate(more collisions)
4.catalysts:increase rate of chemical reactions without themselves being changed in the reaction… enzymes are biological catalysts
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Chemical reactions
Synthesis (combination reaction): atoms are molecules combine to form a larger molecule
-metabolic synthesis reactions are termed anabolic reactions
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Chemical reactions
Decomposition reaction: a molecule is broken down into smaller molecules, or its constituent atoms
-metabolic decomposition reactions are termed catabolic reactions
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Chemical reactions
Exchange (displacement) reaction:components of the reactant molecules change partners, resulting in different molecules as products
-ex: neutralization reactions (strong acid + strong base -> salt+water)
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Biochemistry
Organic molecules:carbon based molecules
-carbon atoms are bonded mainly to atoms of hydrogen, oxygen, and nitrogen, as well as some other atoms
-always contain carbon and hydrogen
-always covalent bonding
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Inorganic molecules: molecules that do not contain carbon and hydrogen (salts, strong acids and bases, metal compounds)
-usually ionic bonding
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Properties of water:
-resists changes in temp (increases collisions part due to hydrogen bonding)
A. Calorie:amount of energy required to raise temp of 1 gram of water by 1 degree Celsius
B. Other covalent;y bonded liquids require about half this energy
C. Important for organisms(mostly water) maintains normal internal temps. (Homeostasis)
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Water has a high heat of vaporization
High boiling point (100degrees Celsius)
Heat of vaporization 540 calories
Energy needed to break hydrogen bonds
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Water is the universal solvent:
-many compounds dissolve in water (separate into ions)
-ionic compounds :salts
-polar covalent compounds
-water is a polar molecule: the negative ends of water molecules are attracted to positively charged ions, and the positive ends of water molecules are attracted to negatively charged ions
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Reactivity:water is an important reactant in many chemical reaction; used in the buildup and breakdown of organic macromolecules
-dehydration synthesis( condensation reactions: formation of a bond with removal of water
-hydrolysis reactions:breaking of a bond by the addition of water
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Cushioning
Cushioning: water helps protect certain body organs from physical trauma (ex: CSF in brain)
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Mixtures: 2 or more substances physically intermixed
-no chemical bonding occurs between components of a mixture
-can often be separated by physical means (unlike compounds, which can only be separated by chemical means)
-3 basic types of mixtures: solutions, colloids, and suspensions
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Solutions
Homogeneous mixtures(components may be solids,liquids, or gases)
Ex salt water
-the component in greater concentration is the solvent;mother components in greater concentration is/are the solutes
-concentration can be expressed in % solute (70% NaCl) or molarity (moles/liter) (0.5 M NaCl)
1 mole of solute=avogadros number of solute particles (6.02x10 ^23)
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Colloids
Heterogeneous mixtures, often translucent
-large solute molecules, but remain dispersed
-colloids scatter light (separate wavelengths)
-capable of sol-gel transformations (reversible change from fluid to gel state)
Ex: jell-o, cytosol (material inside cell)
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Suspensions:
Heterogenous mixtures with large solutes that tend to settle out
(Ex:sand and water)
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Ph scale(power of hydrogen)
Indicates acidity or basicity of solution
-ranges from 0 (strong acid) to 14 (strong base): ph=7 is neutral
-water ionizes to release hydrogen ions and hydroxide ions
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Acid
Molecules that release hydrogen ions when dissolved in water’-acids are hydrogen ion (proton) donors
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Base
Molecules that releases hydroxide (OH-) ions, or increase the number of hydroxide ions available, when dissolved in water
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Salt
Ionically-bonded molecule that dissociates into cations and anions in solution
-in the body, salts are electrolytes that conduct electricity and provide essential chemical elements in body fluids
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Buffers
Maintain stable ph of solution (resist changes in ph)
-buffers can take up excess hydrogen or hydroxide ions
-buffers have acidic and basic components
-blood uses carbonic acid-bicarbonate ion(basic) buffer system
-normal oh of blood is between 7.35 and 7.45
-bicarbonate ions take up added hydrogen ions, and carbonic acid takes up,excess hydroxide ions
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Carbohydrates: contain carbon, hydrogen, and oxygen atoms)
Monosaccharides: simple sugars with a backbone of 3 to 7 carbon atoms
-GLUCOSE is a 6 carbon sugar (hexose) founds in the blood of animals, and FRUCTOSE is a hexose found in fruits
-ROBOSE is a 5 carbon sugar (Pentose) founds in rna (in dna, the pentose sugar is deoxyribose)
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Disaccharides:2 monosaccharides joined by condensation
-maltose (a disaccharide in the digestive tract)= glucose + glucose
-lactose(a disaccharide in milk)= glucose+galactose
-Sucrose(a disaccharide in fruits and veggies)= glucose+fructose
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Polysaccharides
1.glycogen is a highly branched polymer of glucose, and is the storage form of carbohydrates in animal cells
2. Starch is a more moderately branched polymer of glucose; and is the storage form of carbohydrates in plant cells
3.cellulose is an unbranched polymer of glucose, with adjacent chains held together by hydrogen bonds, giving it a very rigid structure
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Lipids
In the form of neutral fats
One triglyceride=glycerol +3 fatty acids
-Glycerol has 3 carbon atoms and 3 hydroxyl groups
-fatty acids have a long hydrocarbon chain with a carboxylic acid group at one end
-condensation joins a fatty acid to each of the hydroxyl groups in glycerol
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Saturated fatty acids
Each carbon atom in the fatty acid molecules have the maximum number of bonded hydrogen atoms (each carbon is saturated with hydrogen atoms) there are no c=c double bonds)
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Unsaturated fatty acids
One or more carbon atoms in the fatty acid molecule has less than the maximum number of bonded hydrogen atoms; there are one or more c=c double bonds in animal called, neutral fats are in the form of fats
-fats are solid at room temp
-fats contain more saturated fatty acids
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Phospholipids
Glycerol+ 2 fatty acids +1 polar (phosphate containing) head group (instead of third fatty acids in triglyceride)
-Allows molecules to have hydrophobic end (2 fatty acids) and hydrophilic (phosphate) end
-these molecules are the sub units of biological me,brands in cells: the polar head group is in contact with water on the inside and outside of the cell, and the hydrophobic fatty acid chains are buried in the center of the membrane
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Steroids
Are composed of 4 fused carbon rings plus some variable functional side group
-cholesterol is a structural component of the plasma membrane in animals, and is used in the synthesis of vitamin d and bile salts
- cholesterol is a precursor from of steroid that is modified to produce several other types of steroids
-steroids function as hormones in animal cells
-accumulation of large amounts of these bulky molecules in animals can lead to reduced blood flow and hypertension (high blood pressure)
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Proteins
Proteins are composed of chains of amino acids in living cells of living organisms
-there are 20+ different amino acids in cells of living organisms
-amino acids have a basic core structure plus an additional functional side chain
-each amino acid has a central carbon bonded t an amino group, a carboxylic acid group, a hydrogen atoms, and the remaining side chain
-condensation of two amino acids in a growing polypeptide chain results in the formation of a polypeptide bond; the peptide bond joins the amino group of one amino acid to the carboxylic acid of the previous amino acid in the polypeptide… the r group do not normally bond between amino acids
-hydrolysis of peptide bonds occur between specific amino acids in a protein by the activity of specific enzymes
-R groups can be nonpolar and hydrophobic, or polar and hydrophilic, depending on the atoms present
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Polypeptide
A chain of many amino acids joined by peptide bonds
-a protein can be composed of one or several polypeptide chains
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Protein structure
Primary structure:the sequence of amino acids in a polypeptide chain
Secondary structure: the formation of discrete structures involving several amino acids with in a polypeptide chain (held together by hydrogen bonds)
A. Alpha helices
B.beta pleated sheets
Tertiary structure: the conformation of the polypeptide chain following interactions of regions of secondary structure
-interactions can involve hydrogen binds, ionic bonds and covalent bonds
-polypeptide folds into specific, consistent and reproducible structures involving several
Quaternary structures: structure following interactions and bonding between two or more (the same or different) polypeptide chains
-hydrogen or ionic bonding between polypeptide chains
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Denaturatiom
Disruption of specific 3d structure of a protein by increasing temp or changing ph
-may be reversible
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Enzymes
Increase the rate of a chemical reaction by lowering its activation energy without increasing the temp or pressure within a cell
-most consist of a protein apoenzyme and a nonprotein cofactor, an organic cofactor is called a coenzyme.. the whole enzyme is the holoenzyme
-often assist each step of a metabolic pathway
-each enzyme reacts with a specific substrate to form a specific product, the part of an enzyme molecule where the substrate binds is called the active site
-enzymes are not changed by chemical reaction
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Nucleic acids
Are ploymers of nucleotide monomers
-a nucleotide= a pentose sugar+ a phosphate + a nitrogenous base
-in RNA, the pentose is ribose
-in DNA, the pentose is deoxyribose
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DNA
Is the genetic material of the cell(inherited by parents)
-composed of a sequence of four different nucleotides
-the 4 nucleotide subunits of DNA are named after the nitrogenous base each contains, 4 bases are; adenine(A), cytosine(C), guanine(G), thymine(T)
-Adenine and guanine are purine bases, and have very similar structures
-cytosine and thymine are pyrimidine bases, and have very similar structures
-DNA forms a double helical structure in which two chains bond together, the sugar and phosphate groups are on the outside, and the nitrogenous bases interact by hydrogen bonding in the middle of the double helix
-A pairs with T thru 2 hydrogen bonds
-C pairs with G thru 3 hydrogen bonds (stronger)
-the 2 strands of the double helix are complementary
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RNA
-is synthesized from 1 strand of DNA
-RNA does not form a double helix , it is single stranded
-also uses 4 nucleotide subunits; however, uracil (U) replaces thymine in RNA
-sometimes RNA molecules pair with complementary bases within the single RNA strand, forming loop,structures which may be necessary for some function in the cell
-some RNA molecules are structures in the cell (ribosomal RNA) and some have enzymatic activity
-the major function of RNA in the cell is carrying the genetic information for proteins from genes in the nucleus to ribosomes in the cytoplasm
-this RNA intermediate between genes and proteins is called messenger RNA (mRNA)
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ATP (adenosine triphosphate)
ATP is a nucleotide that provides energy for most of the chemical reactions occurring within cells
ENERGY is released when the terminal phosphate is hydrolyzed (cleaved by addition of water)
The overall reaction is: ATP => ADP +P+Energy
The energy released from this Exergonic reaction is used to drive forward energy absorbing (Endergonic) reactions in cells
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Cells
The basic structural and functional units of living things
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Plasma membrane
Flexible outer surface of cell; selective barrier that regulates flow of materials into and out of cell-maintains internal environment
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Cytoplasm
All cellular contents between plasma membrane and nucleus
-contains organelles: small, membrane- bounded bodies with a specific structure and function (mitochondria, chloroplasts, lysosomes) in cytosol (semifluid medium between nucleus and plasma memenrane
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Nucleus
Large organelle that stores DNA in the form of chromosomes containing genes
-cell wall in plant cells, fungi, protists, bacteria… for this course we’ll focus on animal cells, which have no cell wall
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Plasma membrane
Outer boundary of cells
-phospholipid bilayer semipermeable and selectively permeable
-functions in regulation of passage of molecules into and out of cell
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Fluid mosaic model
The membrane is a fluid phospholipid bilayer, capable of lateral movement of membrane components, in which various protein molecules are either partially or wholly embedded
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Membrane components
-phospholipids:create bilayer
-Amphipathic: have polar and non polar parts
-glycolipids: protective function, and cell identity
-cholesterol: bulky; controls (reduces) permeability
-proteins: also glycoproteins can be transmembrane(trans the entire membrane) or embedded in either the cytoplasmic or extracellular side of the membrane
-glycoproteins (and glycolipids) function in cell-cell recognition (cell fingerprint); important in transplantation
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Glycocalyx
The plasma membrane is covered by a carbohydrate layer that strengthens the cell and enhances attachment to substrates or other cells
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Fluidity
Both phospholipids and membrane proteins are capable of lateral movement in the plasma membrane
-phospholipids rarely change from cytoplasmic to extracellular side of the bilayer, or vice versa, since the polar head group would have difficulty moving thru the hydrophobic center
-the amount of movement is dependent on composition of phospholipids, glycolipids, and cholesterol
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Types of membrane proteins
Chanel proteins:
Create transient hydrophilic channel for small molecules and ions to flow into and out of cell
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Types of membrane proteins
Carrier proteins:
Selectively interact with small molecules or ions to assist them across the membrane
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Types of membrane proteins
Cell recognition protein:
Cell identity; individual specific groups on extracellular side of membrane
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Types of membrane protein
Receptor protein:
Interacts with specific molecule to transmit some type of signal or communication (electrical, chemical, or contact) between cells
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Types of membrane proteins
Enzymatic protein:
Catalyzes (speeds up) some specific reaction which results in a cellular response
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Plasma membrane in semipermeable and selectively permeable
Some molecules may pass through freely(water); others must be assisted across
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Gradients across plasma membrane
-concentration gradient:difference in concentration in a molecule from one place to another
-Allows molecules to enter and exit cell by diffusion
-electrochemical gradient: due to membrane potential ( difference in voltage across membrane ) and concentration gradient
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Diffusion
Movement of molecules from a region of higher concentration to a region of lower concentration (down concentration gradient)
-lipid soluble molecules, gases(oxygen, carbon dioxide) and water can diffuse across the plasma membrane components
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Osmosis
Diffusion of water across a differential permeable membrane
-important in water retention
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Tonicity
The strength (solute concentration) of a solution in relation to osmosis
-in cells, the solute concentration of a solution with respect to that solute concentration inside the cell
-isotonic solution:the net solute concentration of the solution equals that inside of cell
-hypotonic solution: the net solute concentration of the solution is less than inside the cell; animal cells will swell and eventually bursts
-hypertonic solution:the net solute concentration of the solution is greater than inside the cell; cell shrinks
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Facilitated diffusion
Passage of small molecules(glucose,amino acids) across the plasma membrane even though they may not be lipid soluble
-A carrier protein assists movement of molecules down concentration gradient
-no energy is required
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Filtration
A pressure gradient pushes solute containing fluid from area to high pressure to area of lower concentration pressure
-forces water and solutes thru membrane or capillary wall by hydrostatic pressure
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Active processes
Active transport: movement of small molecules or ions across membrane assisted by carrier protein and against concentration gradient-from region of lower concentration to region of higher concentration
-requires energy ATP
-Secondary active transport:uses energy derived from primary active transport to drive other substances across membrane
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Vesicular (membrane assisted) transport
-transport of macromolecules into or out of cell in vesicles
-vesicle: small, spherical sac hat has budded off existing membrane
-requires energy ATP
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Exocytosis
Moves macromolecules out of cell in vesicles budding off plasma membrane
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Endocytosis
Moves macromolecules into cell thru vesicles budding off plasma membrane
-phagocytosis: endocytosis of large food particles or invading cells (bacteria)
-common in macrophages of the immune system
-pinocytosis:endocytosis of a liquid or very small particles(sampling of extracellular environment)
-receptor mediated endocytosis: endocytosis involving a receptor protein and its ligand (molecule it binds)
-receptor proteins cluster together in clathrin coated pits
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Transcytosis
Vesicles undergo endocytosis on one side of cell, move across cell and then undergo exocytosis at other side of cell
-contents of vesicle released outside cell as vesicle fuses with plasma membrane
-occurs across endothelial cells in blood vessels to move materials between blood plasma and interstitial space
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Cytoplasm
The contents of the cell between the plasma membrane and nucleus
-cytosol:the fluid portion of the cytoplasm
-contains organelles (small functions within cells)
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Cytoskeleton
Composed of microfilaments, microtubules and intermediate filaments
-functions in maintaining shape of cell and movement of subcellular structures
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Microfilaments
Thinnest elements of cytoskeleton; help generate movement and provide mechanical support
-Actin filaments combine with myosin in muscle cells to enable muscle movement
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Microtubules
Composed of tubulin dimmers coiled into tubelike structures
-concentrated and arranged as rings of nine doublets or triplets in centrioles, cilia, and flagella
-Microtubules involved in movement associate with motor proteins kinesin and dynein
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Intermediate filaments
Have structural roles throughout the cell(resist stress)
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Microvilli
Very small, finger like projections that project from a free surface of some cells
-supported by Microfilaments
-increases surface for absorption
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Centrosome
Located near nucleus; consists of centrioles and pericentriolar material
-centrioles:cylindrical structures composed of 9 clusters of three microtubules (triplets) arranged in circular pattern
-pericentriolar material consists of hundreds of tubulin complexes
-involved in organization of spindle fibers for chromosome movement during mitosis
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Cilia and flagella
Composed of microtubules(9+2 pattern); used in movement
-cilia present in some unicellular protists(paramecium) and cells of respiratory tract in animals
-flagella present in some unicellular protists (euglena) and sperm cells
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Ribosomes
Site of protein synthesis in the cell
-free in cytoplasm (poly ribosomes) or associated with rough endoplasmic reticulum
-2 subunits (large and Small); MRNA is threaded thru subunits during translation (protein synthesis)
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Endomembrane system
Includes Golgi apparatus, endoplasmic reticulum, vesicles, and nuclear membrane
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Endoplasmic reticulum
Network of folded membranes that extends from the nucleur envelope throughout the cytoplasm
-ROUGH ER: associated with ribosomes; proteins translated on ribosomes associated with the rough ER will be transported and/or secreted outside cell
-begins processing and modification of these proteins
-SMOOTH ER: synthesizes phospholipids in all cells; various other cell type specific functions
-synthesizes steroid hormones in tests, and detoxifies drugs in liver cells
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Golgi complex
Completes modification of proteins from rough ER (proteins transported to Golgi in vesicles)
-composed of stacks of flattened membraneous sacs called Golgi Cisternae
-modification of proteins and lipids
-also transports organic molecules in vesicles; some become lysososmes
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Lysosomes
Vesicles with digestive enzymes to break down macromolecules and cell debris
-loss of some or all lysosome function in inherited dose orders may lead to accumulation of unwanted molecules
-autophagy: digestion of worn out organelles
-autolysis: destruction of the cell
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Microbodies
Smaller version of lysosomes with specific enzyme activities
-PROTEASOME: destroy unneeded ,damaged or faulty proteins in cells
-PEROXISOMES: are microbodies that contain enzymes for oxidizing certain organic molecules with the release of hydrogen peroxide
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Vacuoles
Larger membrane bounded organelles
-function in storage
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Mitochondrion
Produces energy
-site of cellular respiration (ATP)
-bounded by 2 membranes:outer mitochondrial membrane and inner mitochondrial membrane
- also have folded membrane system (folds to cristae, inner fluid filled space is the matrix)
-extensive membrane system needed in both chloroplasts and mitochondrion for ATP synthesis
-Mitochondria have their own DNA chromosome with genes and their own ribosomes
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Nucleus
Stores genetic information in cells
-the nucleus is bounded by a porous double membrane , the nuclear envelope, which regulates passage of molecules into and out of the nucleus (thru nuclear pores)
-DNA is organized into distinct chromosomes
-chromosomes are packaged with proteins to form chromatin
-chromatin exists in a semifluid medium called nucleoplasm
-dark regions within the nucleus are nucleoli
-within each nucleolus, ribosomal RRNA is produced and joins with ribosomal proteins to form ribosomes
-the structure of the nucleus is maintained by the nuclear matrix, which contains a protein network called the nuclear laminate, which also provides chromatin attachment sites to maintain organization
-genome: all the dna within the nucleus of the cell
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Gene expression
Transcription:
DNA is transcribed to RNA in the nucleus
3 types of RNA can be made
-mRNA(messenger rna) : directs the synthesis of a protein
-rRNA(ribosomal rna): rRNA along with proteins comprise the structure of the 2 subunits of the ribosome
-tRNA(transfer rna): binds to an amino acid and delivers it to the ribosome during protein synthesis; has anticodon that binds to mRNA codon
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Translation:mature RNA
Is translated to protein in the cytoplasm
-translation occurs in the ribosomes
-many ribosomes may synthesize protein from the same mRNA molecule at the same time(poly ribosomes)
-tRNA molecules carry amino acids to the ribosome during translation
-ribosome subunits associate immediately prior to translation, and dissociate following translation
-ribosomes bind mRNA at the 5’ cap, assisted by rRNA components, and begin translation, usually at the first AUG codon
-the initiator AUG binds to the P site to begin translation… all following tRNAs bind to the A site, and transfer their amino acids to the growing polypeptide at the P site
-one of the 3 stop codons (UAA,UAG,UGA) signals the ribosomes to stop translation of the mRNA
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Cell division
-cell division involves nuclear division and cytokinesis(division of cytoplasm)
-normally most eukaryotic calls have 2 copies of each chromosomes; the 2 chromosomes of each pair are called homologous chromosomes
-the reproductive cells have only one copy of each chromosome
-human somatic cells have 23 pairs of chromosomes; gametes have 23 chromosomes
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Cell cycle
Consists of interphase and mitosis
Interphase consists of G1, S, and G2
-S phase: synthesis phase of the cell cycle, when the DNa is replicated
-G1 phase:the growth stage during which organelles increase in number to produce enough for two new cells
-G2: also a growth stage in which metabolism provides new metabolites and energy for the mitosis division
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DNA synthesis
DNA replication is carried out by the enzyme DNA polymerase, as well as some additional protein factors
-DNA helicase unwinds the double helix in preparation for replication
-replication is unidirectional. One strand is synthesized in the 5’ to 3’ direction… the fragments are sealed together by DNA ligand
-DNA polymerase has a proofreading activity to correct replication errors. The corrected error rate is 1 in 1 billion bases
-DNA replication is semiconservation: each newly replicated DNA molecule consists of 1 old strand from the original double stranded DNA molecule, and 1 newly synthesized strand
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Mitosis:M phase
-prophase: chromatin condenses and the nuclear membrane begins disintegration
Mitotic spindle begins to assemble from Microtubules in centrosome, where centrioles from short asters prior to formation of spindle fibers
-in late phosphate, chromosomes attach to the spindle fibers, and are moved toward the center of the cell
-Metaphase: chromosomes move toward opposite poles of the cell due to disassembly of spindle fibers
-Anaphase: chromosomes move toward opposite poles of the cell due to disassembly of spindle fibers
-Telophase: chromosomes are at opposite poles of the cell; nuclear envelope reforms around each set of chromosomes, and spindle disappears
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Cytokinesis
Cells divide by means of a cleavage furrow
