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What is an Atom?
the smallest particle of an element that has the characteristics of the element
the smallest particle of an element that retains the properties of the element
What is a molecule?
two or more atoms bonded together (by ionic or covalent bonds)
a particle composed of one or more atoms held together by chemical bonds; the smallest particle of a compound that displays all the properties of that compound.
describing a molecule that contains both carbon and hydrogen
LOOK OVER CAR/BUTTERFLY EX.
Scientific Theory: General explanation of natural phenomena. Extensively and reproducibly tested using the scientific method. All data and observations support it. Similar to a principle or natural law (e.g. the theory of gravity)
Everyday Theory: pretty much an educated guess.
1. COMPOSED of Cells
2. HOMEOSTASIS (Maintain constant internal conditions)
3. Response to STIMULI
4. Acquire and use materials for ENERGY
5. CELL GROWTH
6. Potential to REPRODUCE
7. Have the collective ability to EVOLVE
a subatomic particle that is found in the nuclei of atoms; it bears a unit of positive charge and has a relatively large mass, roughly equal to the mass of a neutron.
Clustered in the middle (“Atomic Nucleus”)
Positive (+) charge.
a subatomic particle that is found in the nuclei of atoms, bears no charge, and has a mass approximately equal to that of a proton
Clustered in the middle (“Atomic Nucleus”)
The number of neutrons doesn’t always match the number of protons.
When an atom doesn’t have an equal number of protons and neutrons
a subatomic particle, found in an electron shell outside the nucleus of an atom, that bears a unit of negative charge and very little mass
Constantly moving in a orbit around the nucleus
Determine whether atoms interact or not to form a molecule
Element: A substance that cannot be broken down or changed by natural processes. Oxygen, Carbon, Gold. Water (H2O), is not an element
Molecule: Two or more atoms bound together by a chemical bond i.e. Water H2O
Compound: a molecule made up of 2 different atoms. H2 vs. H20
the number of protons in the nuclei of all atoms of a particular element
protons + neutrons + electrons
*ELECTRONS ARE OF NEGLIGIBLE WEIGHT!* so really just protons + neutrons
a region in an atom within which electrons orbit; each shell corresponds to a fixed energy level at a given distance from the nucleus.
The first shell will only hold up to 2 electrons, but the second shell holds up to 8.
Electrons are only stable when their outer shell is full. 8 (or 2 for hydrogen and helium).
Unstable atoms want to become stable to attaining a full outer shell.
an attraction between two atoms or molecules that tends to hold them together. types of bonds include covalent, ionic and hydrogen.
process that forms or breaks chemical bonds between atoms.
requires energy to happen.
2 Types: exergonic and endergonic
an electron is transferred, creating positive and negative ions that attract one another
*NaCl* (think Na PLUS Cl MINUS)
What is an Ionic Bond?
Ions with opposite charges attract one another, and the electrical attraction between positively and negatively charged ions.
They are weak and easy to break.
a chemical bond formed by the electrical attraction between positively and negatively charged ions
To become stable, atoms interact with other atoms to lose, gain, or share electrons
The electrical attraction between cations (+) and anions (-) pulls atoms together
Pretty weak and easy to break
electrons are shared
What is a Covalent Bond?
When atoms share electrons with one another.
They are strong and hard to break.
There are non-polar and Polar Covalent bonds.
a chemical bond between atoms in which electrons are shared
The sharing of electrons leads to covalent bonds (H2O)
2 charges: Polar and nonpolar
Strongest and hard to break
Essential to life because they hold together biological molecules.
slightly positive hydrogen in a polar molecule attracts the slightly negative pole of a nearby polar molecule
What is a Hydrogen Bonds?
The attraction between slightly positive hydrogen and a slightly negative oxygen or nitrogen located in a nearby molecule or in another part of the same molecule
(very common in water)
the weak attraction between a hydrogen atom that bears a partial positive charge (due to polar covalent bonding with another atom) and another atom (oxygen, nitrogen, or fluorine) that bears a partial negative charge; hydrogen bonds may form between atoms of a single molecule or of different molecules
H2O for example. Cannot have hydrogen bonds unless you first have a molecule that has polar covalent bonds. Produce positive and negative regions These regions repel and attract each other, just like ions (or magnets) This bond is the weakest and very easy to break.
Not one atom sticking to one atom, but one MOLECULE being attracted to ANOTHER.
Polar Covalent Bonds
Electrons shared unevenly; positive and negative areas exist.
Non-Polar Covalent Bonds
Electrons shared evenly; neutral all over.
a covalent bond with unequal sharing of electrons, such that one atom is relatively negative and the other is relatively positive.
a covalent bond with equal sharing of electrons
tendency of molecules of a substance to stick together
*water traveling up a tree*
the tendency of the molecules of a substance to stick together
cohesion of water molecules along a surface
*spiders rely on surface tension to move across the surface of ponds; why belly flops hurt*)
the property of a liquid to resist penetration by objects at its interface with the air; due to the cohesion between molecules of the liquid
water-soluble molecules; water molecules are attracted to and can surround (thereby dissolve) ions or polar molecules
pertaining to molecules that dissolve readily in water, or to molecules that form hydrogen bonds with water; polar.
water-insoluble molecules that repel nonpolar molecules (like fats and oils)
*scared of water!*
pertaining to molecules that do not dissolve in water or form hydrogen bonds with water; non polar
solutions where H+>OH-
*lemon juice, vinegar*
a substance that releases hydrogen ions (h+) into solution; a solution with a pH less than 7
referring to a solution with an h+ concentration exceeding that of OH-; referring to a substance that releases H+
solutions where OH->H+
*baking soda, bleach, ammonia*
ice is less dense than liquid water; water molecules spread apart slightly during the freezing process
*ice floats in water, preventing ponds from freezing to the bottom!*
Must have both CARBON and HYDROGEN
Made and used by living organisms
Also called biological molecules
All use COVALENT BONDS
Carbon makes up the backbone of organic molecules
a small organic molecule several of which may be bonded together to form a chain called a polymer
Small organic molecules (called monomers) are joined
Monomers are joined together through dehydration synthesis.
a molecule composed of three or more (perhaps thousands) smaller subunits called monomers, which may be identical (for example, the glucose monomers of starch) or different (for example, the amino acids of a protein)
a chemical reaction in which two molecules are joined by a covalent bond with the simultaneous removal of a hydrogen from one molecule and a hydroxyl group from the other, forming water; the reverse of hydrolysis.
the chemical reaction that breaks a covalent bond by means of the addition of hydrogen to the atom on one side of the original bond and a hydroxyl group to the atom on the other side; the reverse of dehydration synthesis
I. What is a Carbohydrate?
Composed of Carbon, Hydrogen, and Oxygen in a 1:2:1 ratio. Used primarily as an energy source.
a compound composed of carbon, hydrogen and oxygen, with the approximate chemical formula (CH2O) includes sugars, starches and cellulose
What is a Monosaccharide?
Carbs consisting of just one sugar molecule.
-Usually in rings of 3-7 Carbon
Ex: glucose; primary energy source of cells...also fructose, ribose, and deoxyribose.
the basic molecular unit of all carbohydrates, normally composed of a chain of carbon atoms bonded to hydrogen and hydroxyl groups
*SUCROSE, LACTOSE, MALTOSE!*
What is a Polysaccharide?
Three or more monosaccharides linked together.
-"Complex Carbohydrates" not sweet
-2 main functions:
1) Energy Storage: starch by plant and Glygoen by animals
2) Structural Support: cellulose and chitin
a large carbohydrate molecule composed of branched or unbranded chains of repeating monosaccharide subunits, normally glucose or modified glucose molecules; includes starches, cellulose and glycogen
*BEEF FAT, BUTTER!*
bombardment of oils with Hydrogen and Fatty Acids pick them up and become Saturated (solid)
-don't spoil quickly so therefore useful in commercial food products but animal fat costs more and plant oils dont.
-preservatives to make food last longer
a type of fat, produced during the process of hydrogenating oils, that may increase the risk of heart disease. the fatty acids of trans fats include an unusual configuration of double bonds that is not normally found in fats of biological origin
*LOOKS LIKE ZIPPER!*
What is a Phospholipid?
a lipid consisting of glycerol bonded to two fatty acids and one phosphate group, which bears another group of atoms, typically charged and containing nitrogen.
a lipid consisting of glycerol bonded to two fatty acids and one phosphate group, which bears another groups of atoms, typically charged and containing nitrogen. a double layer of phospholipids is a component of all cellular membranes
What are Proteins functions?
Structural, movement, defense, storage, signaling, catalyzing reactions.
Amino acids, 4 structures.
Mono - amino acid
Poly - peptide
Multiple peptides are called polypeptides
POLYPEPTIDES are officially PROTEINS
Peptide Bond vs Polypeptide Bond
Tertiary (now functional)
Nucleotides (three part structures)
an organic molecule composed of nucleotide subunit; the two common types of nucleic acids are ribonucleic acid and deoxyribonucleic acid
Starting block steroid; vital component of the membranes of animal cells
Make these hormones:
provide a binding site outside cell for hormones/other molecules that need to produce a response inside a cell
flags that ID a cell as "self" to prevent attack by immune system
usually on the inside of the membrane promote chemical reactions inside cell
a biological catalyst, usually a protein, that speeds up the rate of specific biological reactions
physically connect neighboring cells to each other
a solvent containing one or more dissolved substances
a liquid capable of dissolving (uniformly dispersing) other substances in itself.
A physical difference or concentration between two adjoining regions of space.
Molecules in fluids move in response to concentration gradients to reach equilibrium.
Exist both inside and outside the cell.
-Random motion produces a net movement from regions of high concentration to regions of low concentration.
Active transport, exocytosis, and endocytosis.
Requires the use of energy.
Using (with) a concentration gradient
-no energy requided
diffusion of water across membranes; Water diffuses from a region of high to low water concentration across a membrane
solution is one with a greater solute (e.g. salt) concentration
solution has a lower solute concentration.
against a concentration gradient
isolates cell contents from enviornment
A flexible boundary that controls the movement of substances into and out of the cell
All eukaryotic cells
Plasma Membrane Functions:
Isolate cell contents (phospholipids)
Regulate exchange of substances
Communicate between cells
Create attachments with other cells
Regulate biochemical reactions
everything inside a cell membrane and outside nucleus membrane
Cilia an Flagella
combination of structures that produce an internal framework
-Provides support, anchors structures, allows transport with cell (gives cells shape)
membrane-bound central region that contains DNA
Endoplasmic Reticulum (ER)
1) Rough (w/ ribosomes): makes proteins
2) Smooth (no ribosomes): makes lipids
organelle inside cells of mesophyll where photosynthesis takes place.
-contain a set of special pigments that absorb light
-chlorophyll is the most important that the plant uses to make sugar
energy is captured from the sun and stored as chemical energy and some basic molecules to make sugar.
the key light-capturing pigment moleculr in chloroplasts that strong absorbs violet, blue, and red light, but reflects green.
How leaves take in CO2 and release O2.
Constantly changing because they open stomata just enough to exchange gases, but not enough to lose too much water.
Chloroplasts are filled with a fluid called stroma.
the Calvin Cycle occurs in the stroma.
disc shaped sacs found in the stroma which contain pigments for chlorophyll.
where the light-dependent reaction occurs.
Takes place in the thylakoids. Sunlight is converted to chemical energy and stored in energy-storing molecules. ATP and NADPH, O2 is given off as waste
- H20 + SUNLIGHT = ATP +NADPH +O2
The first stage of glucose breakdown.
breaks glucose into 2 pyruvates and 2 ATP.
Occurs outside mitochondria in the cytoplasmic fluid.
small sections of DNA with discrete instructions
physical location of a gene on a strand of DNA "its address"
Very long (millions of base pairs) double strand of nucleotides.
What is DNA?
Deoxyribonucleic Acid (organic)
combinatiom of one strand of DNA and many support proteins
Principle of why we regulate cell cycle
cell division with faulty DNA is BAD. Irregularity detected by enzymes at any step should prevent cell division.
Homologous chromosome (homologues)
a chromosome that is similar in appearance and genetic information to another chromosome which it pairs during meiosis
a cell with pairs of homologous chromosomes
-Typical human cell
a cell that has only one member of each pair of homologous chromosomes
In humans, a haploid cell contains...
one of each of the 22 autosomes, plus either an X or Y sex chromosome, for a total of 23 chromosomes
n + n =
process by which a diploid cell divides into two identical daughter cells (also diploid)
1 cell duplicates everything then divides to make 2 identical daughter cells
Mitosis takes place...
in all eukaryotic organisms and occurs in body cells
Parent cell of mitosis is...
each daughter cell in mitosis receives...
one copy of each chromosome and roughly 50% of cytoplasm (and organelles)
In eukaryotic organisms, a type of nuclear division in which a diploid nucleus divides twice to form four haploid nuclei (one parent cell/diploid will form 4 daughter cells/haploid)
In gamete-producing cells
Starts with one diploid cell (parent), then replicates all 46 chromosomes(=46 chromatid pairs) then each cell divides once, and then those cells divide again creating 4 daughter cells
What is the result of meiosis?
4 Daughter cells
each daughter cell in meiosis receives:
23 chromosomes (one homologues of each pair of chromosome)
The only cells that result from meiosis are...
gametes (all other are mitosis)
Purpose of Meiosis:
it is essential for gamete production for sexual reproduction
How does cloning work?
chrom. are removed from the nucleus of a donor egg and then 1 diploid set of chrom. from a normal cell is injected into the egg. The egg is now diploid and it is a genetic clone of donor. The egg is stimulated to divide as if fertilized...
In cloning, after egg is fertilized...
The embryo that develops is implanted into the uterus of the surrogate and the surrogate gives birth to an offspring that does not contain her DNA
Eukaryotic cell cycle is divided into two major phases:
Interphase and Mitotic cell division (mitosis)
the period between cell divisions where chromosomes are duplicated and other cell functions occur, such as growth, movement, and acquisitions of nutrients
Interphase has three sub-phases:
G1, S, and G2.
cell growth and differentation; newly created cells begin interphase here where the cell grows, matures and the decision is made to divide or not.
S: Synthesis of DNA
Duplication of chromosomes
cell growth and preparation for cell division; final stage before mitosis
Mitotic cell division
the division of one parental cell into two daughter cells; occurs after G2 phase
Cell cycle regulation
progression of cell thru cycle phases is very carefully regulated
3 Regulation Checkpoints
1. G1-S 2. G2-Mitosis 3. During Mitosis
Two options if cell irregularities are detected...
Repair DNA first and if not repairable, cell death is warranted.
programmed cell death (cell suicide); designed to eliminate unhealthy cells
Apoptosis is used...
if cell's DNA is damaged beyond repair, in normal embryonic development, and if a cell malfunctions, is old and needs to be replaced, infected with a virus.
Uncontrolled cell division due to DNA mutations that cause cell cycle regulation to fail and usually requires multiple mutations to overcome multiple checkpoints
Proto-oncogenes mutate to oncogenes and Tumor suppressor genes inactivated
Proto-oncogenes mutate to oncogenes
Oncogenes constantly promote cell division (much like a gas pedal stuck to the floor)
Tumor suppressor genes inactivated
TSG should stop cell division, but mutation inactivates them (as if brakes are broken)
Cell divides quickly and form a tumor, benign tumor, dysplasia, malignant tumor, and metastasis
a large, but normal, mass of cells that is stationary. Can be removed surgically and only dangerous if it damages healthy tissue around it.
cells in benign tumor undergoing change to become abnormal
the dysplasic cell grows into a malignant tumor that is considered to be cancer. these cells break off and move via blood or lymphonic sytem.