Exam 1 Flashcards
1
Q
Atom
A
- the smallest unit of an element that retain’s the elements distinctive properties
- nucleus made of protons (positive) and neutrons, surrounded by electrons (negative)
- electrically NEUTRAL; equal number of protons (positive) and electrons (negative)
2
Q
Characteristics of living things
A
- complex and organized (made of cells, DNA)
- use/process energy
- respond to stimuli
- maintain homeostasis
- evolve (change over time)
3
Q
Atomic number
A
- How many protons in the nucleus
- Defining value for an element
- all atoms of an element have the same atomic number
4
Q
Atomic mass
A
Protons + neutrons
5
Q
Levels of Biological organization
A
- all matter is formed of ELEMENTS
- an ATOM is the smallest particle of an ELEMENT retaining the properties of an element
- ATOMS combine to form MOLECULES
- MOLECULES provide the building blocks for CELLS (smallest unit of life)
6
Q
Electrons
A
electrons = energy = bonds
7
Q
Element
A
A substance that cannot be broken down by ordinary chemical reactions; forms all matter
8
Q
Electrons structure
A
“Parking lots” - outermost electron shell can hold 8 electrons, first shell can hold 2 electrons
9
Q
Ions
A
Positive charge
10
Q
Isotopes
A
- variant atomic forms of an element (atoms of one element may vary in the number of NEUTRONS in the nucleus
11
Q
Chemical bonds
A
Attractive forces holding atoms together in molecules (Ionic, Covalent, Hydrogen)
12
Q
Ionic Bonds
A
- donate, charge, attraction
- weaker than covalent bonds
- atoms that have lost electrons become POSITIVELY charged IONS
- atoms that have gained electrons become NEGATIVELY charged IONS
- oppositely charged ions are attracted to each other and bound into a molecule by IONIC BONDS (negatively charged ion + positively charged ion)
13
Q
Covalent Bonds
A
- strongest bonds
- atoms with partially full outer electron shells can SHARE electrons (empty parking spot + full parking spot)
- two electrons (one from each atom) are shared in a COVALENT BOND (exists in most molecules)
- single, double, triple: how many electrons are being shared, affects equality of sharing and polarity
- polar vs nopolar
14
Q
Polarity
A
- causes curvature or “sticky” molecules; positive and negative charges
- nonpolar = equal sharing of electrons
- polar = unequal sharing of electrons (creates poles)
15
Q
Diatomic molecules
A
Two atoms of the same type
16
Q
Hydrogen Bonds
A
- weakest bonds
- polar molecules have partially charged atoms at their ends; formed when partial opposite charges in different molecules attract each other
- weak individually but can be stronger collectively; become more stable by bonding
17
Q
Reagents
A
- Lugol’s: starch, yellow-brown > blue-black
- Benedict’s: glucose, heat 3 min turns blue > reddish-orange
- Sudan IV: fats, red > red layer
- Biuret’s: protein, light blue > violet
- Ninhydrin: amino acids, purple/violet
18
Q
Hydrophilic
A
Water-soluble molecules (polar)
19
Q
Hydrophobic
A
Water-insoluble molecules (non-polar); hydrophobic interaction = clumping of non polar molecules
20
Q
Properties of water
A
An excellent solvent; neutral pH
- heat storage - stabilizes temperature, protects metabolism
- high heat of vaporization - takes a lot of energy to freeze (ice is less dense and floats - molecules spread apart) or evaporate
- ice formation
- cohesion - hydrogen bonding among water molecules, produces surface tension
- adhesion - water can stick to other things (polar or charges), helps create cohesion
- high polarity
21
Q
pH
A
- proportion of free hydrogen; more free hydrogen ions (hydrogen lacking an electron - just a proton) = more acidic
- low pH (0-6) is acidic, 7 is neutral, high (8-14) is basic or alkaline
22
Q
Functional Groups (def)
A
- atoms that attach to the carbon skeleton
- chemically reactive
- virtually all living organisms use the same basic set
- used to form larger molecules
23
Q
Elements
A
- carbon
- nitrogen
- hydrogen
- phosphorus
- oxygen
- sulfur
24
Q
Functional Groups
A
- hydroxyl (OH+) combines to form water
- methyl (CH3-)
- carbonyl - carbon and oxygen; basics for formaldehyde
- carboxyl - carbon and oxygen, functional group + functional group
- amino - nitrogen + 2 hydrogen
- phosphate
- sulfhydryl- basic in rubber
25
Organic Molecule Synthesis
- dehydration - water as a product of molecule formation
- hydrolysis - water is divided, forms with other molecules
- bio molecules are polymers (chains) of subunits called monomers (joined through dehydration synthesis)
26
Biological Molecules
- carbohydrates
- proteins
- lipids
- nucleus acids
27
Carbohydrates
- carbon, hydrogen, oxygen - ratio of 1:2:1
- Energy dense, most water soluble
- monosaccharides (simple sugars), disaccharides (two simple sugars linked by dehydration synthesis), polysaccharides (chains of simple sugars)
28
Monosaccharides
Simple sugars
- fructose (I.e. Corn syrup, fruit)
- galactose (found in lactose)
Structure:
- backbone of 3-7 carbon atoms
- many -OH and -H functional groups
- usually found in a ring form in cells
- glucose is most common
29
Disaccharides
Two-part sugars
- sucrose (table sugar) = glucose + fructose
- lactose (milk sugar) = glucose + galactose
- maltose (malt sugar) = glucose + glucose
30
Polysaccharides
Complex sugars, chains of monosaccharides
Storage of energy
- starch (plants)
- glycogen (animals)
Structural
- cellulose - polymer of glucose
- chitin - polymer of modified glucose
31
Saturated fats
Solid at room temperature; carbon chain has as many hydrogen atoms as possible
32
Unsaturated fats
Liquid at room temperature; fewer hydrogen atoms, many C=C bonds
33
Wax
Highly saturated, solid at room temperature; strongly hydrophobic
34
Phospholipids
- from plasma membrane around cells
- 2 fatty acids + glycerol + a short polar functional group
- phospholipids have hydrophobic and hydrophilic portions; polar functional groups are water soluble, nonpolar fatty acid tails are water insoluble
- head (hydrophilic), fatty acid tail (hydrophobic)
35
Steroids
- composed of 4 carbon rings fused together
| - e.g. Cholesterol, sex hormones
36
Proteins
- chains of amino acids > peptide bonds; all contain amino and carboxyl groups
- up to four levels of structure, 3D
- enzymes (subgroup) facilitate or speed up reactions
Functions
- structural (keratin, collagen)
- movement (actin and myosin fibers in muscle
- defense (antibodies in blood stream)
- storage (albumin in egg white)
- signaling (growth hormone)
- catalysts (enzymes)
37
Amino acid structure
Variable group (R) at top, hydrogen at bottom, amino group on one side, carboxylic group on other
38
Proteins (4 structure levels)
- primary structure - sequence of amino acids
- secondary structure - helices and pleated sheets
- tertiary structure - complex folding of protein chain
- quaternary structure - multiple protein chains linked together
39
Nucleic acid
- nucleotides are monomers of nucleus acid chains
- nucleotide 3 parts: phosphate group, five-carbon sugar, nitrogen-containing base
Nucleus acid polymers:
- DNA - carries genetic info for protein construction (two chains - double helix)
- RNA - copies of DNA used directly in protein construction
Nucleotide functions
- coenzymes - help enzymes with chemical reactions
- energy carriers - adenosine troposphere carries energy stored in bonds between phosphate groups
- intracellular messengers - carry chemical signals between molecules
40
Cell membrane
Selectively permeable, brings in energy, eliminate/removes wastes, protective
41
Cell theory
1. All organisms are composed of one or more cells
2. Cells are the smallest living things
3. All organisms living today represent a continuous line of descent
4. Cells arise only by division of a previously existing cell
42
Cell attributes
- plasma membrane - encloses cell, regulates material flow
- cytoplasm - fluid interior where metabolic reactions occur
- use DNA as a hereditary blueprint
- use RNA to copy DNA
43
Membrane proteins
- receptors - trigger hormone response
- recognition - identify substances
- enzymatic - synthesize or break apart
- attachment - inner cytoskeleton, other cells
- transport - import/export of -phyllic molecules
44
Diffusion
Movement of a substance from an area of high concentration to an area of low, lower concentration
45
Osmosis
Net movement of water molecules from high to low concentration across a semipermeable membrane
46
Passive transport
Simple diffusion, facilitated diffusion, osmosis
