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148 Cards in this Set
- Front
- Back
what makes us human?
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*growth and development
*homeostasis *reproduction *reacts to stimuli *constantly evolving *movement |
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chemistry
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atoms and molecules; carbs, proteins, fats, DNA
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cellular
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smallest units of life
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tissues
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groups of similar cell types
ex: nervous, muscular, connective, epithelial |
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organs
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made up of all tissue types working together to carry out a specific function
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organ systems
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multiple organs working together to perform a specific function within the body
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organism
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all organ systems working together
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homeostasis
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ability to maintain a relatively constant internal environment in the body
(nervous/endocrine systems aid in this process) |
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feed back loops
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keep the body informed of any changes and also attempt to correct the situation to restore homeostasis
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factors in feedback loop
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*normal controlled condition
*receptor (monitors) *control center *effector (restore normal cond.) |
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negative feed back loop
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immediate reversal!
ex: blood pressure/heart rate |
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positive feed back loop
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intensification!
ex: child birth |
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science
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way of knowing about the natural world; objective; conclusions may be changed or modified as our understanding and technology increase; studied using scientific method
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scientific method
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1. observation
2. hypothesis (testable) 3. experiment 4. conclusion (support/reject hypothesis) 5. scientific theory |
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ulcers
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H. pylori is the cause of gastritis and ulcers
ex: swallowed by humans |
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experimental variable
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variable that is purposely changed or manipulated
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test group
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group of subjects that are exposed to the experimental variable
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control group
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group of subjects that are not exposed to the experimental variable, but receive a placebo instead
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scientific journals
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best source of scientific information
(.edu, .gov, .org) |
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technology
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application of scientific knowledge to human interests
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matter
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is anything that has weight and takes up space
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elements
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are the basic building blocks of matter that cannot be broken down by chemical means
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atoms
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are the smallest units of an element that retain the element’s physical and chemical properties. These bond together to form molecules
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neutrons
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have a neutral charge
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protons
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are positively charged
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nucleus
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made up of neutrons and protons
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electrons
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are negatively charged and orbit around the nucleus
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octet rule
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*an atom can hold 2 electrons in its inner most shell, 8 in the second and 18 in the 3 third
*however, if an atom has 8 electrons in the second or third shell, it is stable and will not react with another atom *if an atom has not satisfied this octet rule, it will react with other atoms to form molecules or compounds |
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molecules
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are made of atoms that are bonded together
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compounds
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are also made of atoms that are bonded together
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ionic bonds
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*atoms in this type of bond donate or receive electrons
*results in a stable outer shell for both atoms *forms charged particles (ions) *will dissociate in water |
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covalent bonds
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*atoms in this type of bond share electrons
*results in a stable outer shell *stronger than ionic bonds; will not dissociate in water |
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hydrogen bonds
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*weaker than ionic or covalent bonds
*can form between hydrogen and oxygen, hydrogen and nitrogen and hydrogen and fluorine *can be found within molecules or in between molecules *not strong enough to form a molecule, but are very important for shaping proteins and DNA *also responsible for some unique properties of water |
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unique properties of water
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*Water is a polar molecule
*high heat capacity (liquid water does not change temperature quickly) *molecules of water cling together *water is a great solvent *liquid at room temperature *frozen water is less dense than liquid water |
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hydrogen bonds
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form between a hydrogen atom in one molecule of water and an oxygen atom in another molecule of water; hydrogen=polar molecule
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polar molecule
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electrons shared unequally; has a charge
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hydrophilic
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molecules that will mix with water
ex: sugars, ions |
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hydrophobic
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molecules that will not mix with water
ex: oils, gases, fats |
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acids
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are substances that dissociate and release hydrogen ions (H+)
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bases
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are substances that take up hydrogen atoms or release hydroxide ions (OH-)
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pH scale
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closer to 0=more acidic
closer to 14=more basic (alkaline) 7=neutral |
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4 major macromolecules
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1. carbohydrates
2. lipids 3. proteins 4. nucleic acids |
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carbohydrates
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*made of subunits called monosaccharides
*made of C, H and O (in a 1:2:1 ratio) *function as short and long-term energy storage *found as simple and complex forms |
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monosaccharide
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1 carbon ring (glucose)
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disaccharide
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2 carbon rings (maltose)
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polysaccharide
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many carbon chains
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glycogen
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storage form in animals
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starch
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storage form in plants
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dehydration synthesis reaction
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the removal of water from two smaller molecules in order to link them together to form one larger molecule
*links together amino acids |
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hydrolysis reaction
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the addition of water to a large molecule to break it down into smaller subunits
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lipids
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*composed of mostly C and H in a 1:2 ratio
*hydrophobic molecules ex: fats, oils, waxes *purpose: used as energy molecules, found in cell membranes and can also be hormones *examples include: saturated and unsaturated fatty acids, triglycerides, phospholipids, and steroids |
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saturated fats
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no double bond between carbons; solid at room temp.; from animals (meat, cheese, etc); increases blood cholesterol levels (LDL-bad) and heart disease
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unsaturated fats
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contain double bonds between carbons; liquid at room temp.; from plants (soy bean, olive oil, etc); lowers blood cholesterol and increases (HDL-good) cholesterol
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fatty acids
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*composed of hydrocarbon chains
*may be 4 to 36 carbons long *the hydrocarbon chain is referred to as the hydrocarbon tail *the other end contains the carboxyl group |
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triglycerides
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*a three-carbon molecule called glycerol is linked to three fatty acids
*found in adipose tissue *long-term energy source and insulation |
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phospholipids
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*composed of glycerol, 2 fatty acids and a phosphate group
*the phosphate containing head is hydrophilic *the fatty acid tails are hydrophobic >>importance: arrange in two layers to form the cell membrane (also known as the phospholipid bilayer) |
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steroids
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*three 6-carbon rings and one 5-carbon ring
*made from a cholesterol base *examples are the sex hormones estrogen and testosterone |
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proteins
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*important for many reasons including:
-contraction -hormones -structure -protection -transport -enzymes |
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enzymes
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speed up chemical reactions; unaltered by the reaction
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amino acid
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subunit of protein; each has a central carbon
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structure of amino acid
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attached to central carbon:
-an amino group -a carboxyl acid group -a hydrogen -R-group |
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peptide bonds
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form between the carboxyl group of one amino acid and the amino group of another
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primary protein folding
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the linear order of amino acids
(determined by DNA; "pearl necklace") |
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secondary protein folding
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folding into pleated sheets and helices
(due to hydrogen bonds) |
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tertiary protein folding
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folding into an even more complex 3-D shape
(due to polar vs. non polar interactions) |
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quaternary protein folding
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two or more tertiary structures
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DNA mutations
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alter protein shape and function causing various diseases and cancer
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nucleic acids
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*examples are DNA and RNA
*subunit is a nucleotide |
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DNA
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deoxyribonucleic acid is inherited and directs protein synthesis
*the two nucleotide chains are held together by hydrogen bonds that form between complementary base pairs -A pairs with T -G pairs with C *the sugar-phosphate backbone forms the sides of the ladder *the nitrogenous bases form the rungs of the ladder |
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RNA
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ribonucleic acid is a temporary helper molecule that assist with protein synthesis
*composed of a single strand of nucleotides *contains the sugar: ribose *the nitrogenous bases are: -Adenine (A) -Guanine (G) -Cytosine (C) -Uracil (U) |
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nucleotide
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3 components
1. sugar 2. phosphate 3. nitrogenous base |
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ATP
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*high energy molecule
*used as currency within the cell to do work *made from glucose, lipids or proteins |
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plasma membrane
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*it is a phospholipid bilayer
*it contains cholesterol for support *it contains glycoproteins and glycolipids *selectively permeable |
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selectively permeable
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the membrane allows some things in while keeping other substances out
(gases go through the easiest!) |
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aquaporn
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protein channel that allows for the passage of water
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diffusion
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going from areas of high concentration to areas of low concentration
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osmosis
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diffusion of water
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concentration
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amount of one substance (solute) dissolved in a given volume of another substance (solvent)
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passive diffusion
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going from high concentration to low concentration (no energy, no transport molecule)
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facilitated diffusion
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going from high concentration to low concentration (no energy, but requires a transport molecule)
ex: amino acids, molecules w. charge, sugars |
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active transport
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requires energy (ATP) going from low concentration to high concentration (up a concentration gradient)
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endocytosis
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transports molecules or cells into the cell via invagination of the cell membrane to form a vesicle
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exocytosis
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transports molecules outside of the cell via the fusion of a vesicle with the cell membrane
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nucleus
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*contains DNA
*surrounded by a nuclear envelope *double membrane with nuclear pores *nucleolus- rRNA is produced |
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cytoplasm
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made up of the:
*cytosol- fluid component *organelles- various structures suspended within the cytosol |
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endoplasmic reticulum
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*continuous with the nuclear envelope
*rough ER- studded with ribosomes that synthesize proteins *smooth ER- lipid and carbohydrate synthesis |
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golgi apparatus
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*receives substances from the ER via transport vesicles
*modifies and repackages for shipping |
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lysosomes
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*vesicles containing digestive enzymes
*break down cellular wastes and help to dispose of ingested particles |
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mitochondria
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*have a double membrane
*manufacture ATP *contain their own DNA |
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cytoskeleton
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proteins that serve to:
*provide a framework for the cell *move substances with in the cell *stabilize organelles |
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microvilli
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fingerlike projections
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cilia
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fine hair-like extensions
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flagella
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single long tail-like structure
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chromosomes
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humans have 46 chromosomes that are in 23 pairs within a cell’s nucleus
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homologous chromosomes
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pairs of chromosomes
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autosomes
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the 22 pairs of chromosomes that control traits that do not relate to gender of an individual
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sex chromosomes
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the 1 pair of chromosomes that contain the genes that do control gender
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diploid
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somatic cells (body cells) have 46 (2N) chromosomes and are called this
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haploid
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sex cells have only 23 (1N) chromosomes and are called this
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cell cycle
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two phases:
1. interphase 2. cell division (mitosis/cytokinesis) |
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interphase
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*G1 stage – cell doubles its organelles; cell grows in size
*S stage – DNA replication occurs *G2 stage – proteins needed for division are synthesized |
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sister chromatids
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once a chromosome duplicates, it is composed of two of these
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centromere
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the sister chromatids are held together at a region called the
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chromatin
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uncondensed chromosomes are referred to as
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centrosome
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the microtubule organizing center of the cell
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aster
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an array of microtubules at the poles (ends of the cell)
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centrioles
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short cylinders of microtubules that assist in the formation of spindle fibers
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mitosis
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*a diploid cell makes and divides an exact copy of its nucleus
*used in cell growth and cell repair *occurs in somatic cells 4 phases: Prophase Metaphase Anaphase Telophase |
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prophase
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*chromosomes condense and become visible
*nuclear envelope fragments *nucleolus disappears *centrosomes move to opposite poles *spindle fibers appear and attach to the centromere |
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metaphase
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*chromosomes line up at the middle of the cell (equator)
*fully formed spindle |
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anaphase
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*sister chromatids separate at the centromeres and move towards opposite poles
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telophase/cytokinesis
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*chromosomes arrive at the poles
*chromosomes become indistinct chromatin again *nucleoli reappear *spindle disappears *nuclear envelope reassembles *two daughter cells are formed by a ring of actin filaments (cleavage furrow)furrow) |
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meiosis
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*two nuclear divisions occur to make 4 haploid cells
*used to make gametes (egg and sperm) *occurs in germ-line cells *has 8 phases (4 in each meiosis I & II) |
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meiosis I
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*prophase I
-homologous chromosomes pair (synapsis) and crossing-over occurs in which there is exchange of genetic information *metaphase I -homologous pairs lined at the equator *anaphase I -homologous chromosomes separate and move towards opposite poles *telophase I -2 daughter cells result each with 23 duplicated chromosomes |
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crossing over
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is the exchange of genetic information between non-sister chromatids during synapsis
(this occurs during prophase I of meiosisand increases genetic variation) |
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meiosis II
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*prophase II
-chromosomes condense again *metaphase II -chromosomes align at the equator *anaphase II -sister chromatids separate to opposite poles *telophase II -4 daughter cells result each with 23 unduplicated chromosomes |
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independent alignment
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occurs in metaphase of meiosis II and makes for the non-identical daughter cells
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nondisjunction
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failure of homologous or sister chromatids to separate during meiosis I or meiosis II.
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monosomy
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cell has only 1 copy of a chromosome
ex: turner syndrome (only one X chromosome) |
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trisomy
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cell has 3 copies of a chromosome
ex: down syndrome (3 copies of chromosome 21) |
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autosomal nondisjunction
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failure of the autosomes to separate
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down syndrome
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trisomy-21; flat face; eye lid folds; mentally retardation; enlarged tongue
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cri du chat
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deletion of a portion of chromosome-5; small head; cat-like cry; severe mental retardation; heart defect
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turner syndrome (X)
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short stature, broad shouldered with folds of skin on the neck, underdeveloped sex organs, no breasts
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klinefelter syndrome (XXY)
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may have underdeveloped sex organs, breast development, large hands and long arms and legs
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poly-X female
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XXX tends to be tall and thin but not usually retarded
XXXX are severely retarded |
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jacobs syndrome (XYY)
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tall, persistent acne, speech and reading problems
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chorionic villi sampling
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suction tube is used to remove cells from chorion, where the placenta will develop
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amniocentesis
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long needle is used to withdraw amniotic fluid containing fetal cell
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locus
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gene at the same location on two different chromosomes
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alleles
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alternate form of gene
ex: black hair vs. red hair |
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ex: EE
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homozygous dominant
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ex: Ee
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heterozygous
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ex: ee
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homozygous recessive
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genotype vs. phenotype
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Ee vs. unattached earlobes
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autosomal recessive disorder
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individuals must be homozygous recessive to have the disorder
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tay sachs disease
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*allele on chromosome 15
*T codes for a functional enzyme that breaks down glycolipids in lysosomes *t codes for a nonfunctional enzyme *glycolipid accumulates and impairs the functioning of the nervous system (both parents must be carriers!) |
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autosomal dominant disorder
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individuals that are homozygous dominant and heterozygous will have the disorder
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huntington disease
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*allele on chromosome 4
*h codes for a functional Huntington protein *H codes for a nonfunctional protein *neurodegenerative disease; muscle spasms, personality changes, dementia, etc. *age of onset-symptoms don't show up until middle age (parent must be HH or Hh) |
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multifactorial traits
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aparticular trait is determined by two or more sets of alleles and environmental influences
*results in a continuous variation of phenotypes ex: height, skin color |
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multiple allele inheritance
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only having two of the possible alleles
ex: ABO blood system |
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codominance
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occurs when the alleles are equally expressed in a heterozygote
ex: type AB blood |
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incomplete dominance
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occurs when the heterozygote is intermediate between the 2 homozygotes
ex: red flower+white flower=pink |
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sex linked inheritance
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*traits are controlled by genes on the sex chromosomes
*X-linked inheritance: the allele is carried on the X chromosome *Y-linked inheritance: the allele is carried on the Y chromosome *most sex-linked traits are X-linked |
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X-linked disorders
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*more often found in males than females because recessive alleles are always expressed in males
*most X-linked disorders are recessive |
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color blindness
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most often characterized by red-green color blindness
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muscular dystrophy
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characterized by wasting of muscles and death by age 20
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hemophilia
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characterized by the absence of particular clotting factors that causes blood to clot very slowly or not at all
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