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bio 2160 > ch 2 cell biology > Flashcards

ch 2 cell biology Flashcards

1
Q

basic unit of all forms of matter is the atom

A

atom is the smallest unit of matter that retains the physical and chemical properties of the element

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2
Q

atoms are made up of?

A
  • subatomic particles: neutrons, protons, and electrons
  • protons (+) and neutrons are found in the nucleus
  • all nuclei have a positive charge
  • electrons (-) and orbit the nucleus. constantly in motion and are attracted to the positively charged nucleus
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3
Q

electron orbitals

A
  • space that is occupied by electrons and by definition can be shared
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4
Q

hydrogen and helium

A
  • every element in the periodic table are in order to be stable and need 8 electrons in its outer orbital to be stable except hydrogen and helium
  • they are the lightest elements and only need 2 electrons in the outer orbital to be stable
  • hydrogen has one electron and one proton
  • helium has 2 electrons meaning its stable and it also has 2 protons and 2 neutrons
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5
Q

chemical behavior of an atom:

A
  • determined by the number of electrons in the outermost electron shell
  • at atom with an incomplete (partially full) electron shell is reactive whereas an atom with a full electron shell is inert, or not chemically active
  • all of the elements on the far right are inert. they will not form chemical bonds bc they dont need to bc they are already full
  • every other element will form chemical bonds, meaning they are reactive
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6
Q

hindenburg - 1937

A
  • a zeppelin or blimp that exploded in 1937 killing 36 people.
  • filled with hydrogen bc its the lightest element (anything lighter than air will float)
  • hydrogen has 1 electron and it wants 2 so it will react.
  • it reacts well with oxygen but anything that reacts with oxygen is combustion.
  • a spark ignited the hydrogen gas and caused the explosion
  • blimps today are filled with helium bc its light and full outer orbital
  • its inert so it wont react with anything and it cant be lit on fire = very safe
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7
Q

a chemical bond is

A
  • an attraction that holds two atoms together
  • a reactive atom will try to fill the valence shell by interacting with other atoms
  • this interaction may result in two atoms forming a chemical bond
  • chemical bonds happen bc 2 or more elements are trying to fill outer orbital
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8
Q

a molecule is

A
  • two or more atoms held together by a chemical bond
  • the smallest unit that retains the physical and chemical properties of a compound
  • identical atoms-molecule-element
  • different atoms-molecule-compound
  • oxygen and hydrogen are found in nature as O2 and H2 these are diatomic molecules
  • NaCl is a compound bc the atoms are different
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9
Q

ions, anions, cations

A
  • ion: charged atom or molecule (either gained or lost an electron)
  • anion: neg charge it has gained an electron
  • cation: pos charge it has lost an electron
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10
Q

covalent bond

A
  • a bond formed when two atoms share pairs of electrons
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11
Q

nonpolar covalent bond

A
  • nonpolar covalent bonds involve electrons being shared equally
  • neither atom will have a charge
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12
Q

polar covalent bond

A
  • polar covalent bond involve sharing electron pairs unequal
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13
Q

polar covalent bond (water)

A
  • water is the most polar things on plant
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14
Q

electronegativity

A
  • atoms ability to attract and hold electrons
  • how much positive charge is in the nucleus
  • the higher the number, the more electronegative an atom is
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15
Q

electronegativity order

A
  • H = 2.2
  • C = 2.6
  • N = 3.0
  • O = 3.4
  • HC, CN, NO - NONPOLAR
  • SEPARTATE = POLAR
  • if they touch they are nonpolar if they dont touch they’re polar
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16
Q

hydrogen bond is

A
  • formed by the charge attraction when a hydrogen atom is covalently bonded to one atom is attracted to a second atom
  • when a hydrogen is involved in a polar covalent bond it will take a partial positive charge bc it has low electronegativity
  • though its stable it still has partial positive. if anything neg comes it will make a slight attraction.
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17
Q

hydrogen bonds

A
  • the bond between a hydrogen and oxygen in a SINGLE water molecule is polar covalent
  • the bond between hydrogen and oxygen in SEPARATE water molecules is a hydrogen bond
  • polar covalent STRONG
  • hydrogen bonds WEAK
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18
Q

polar and ionic substances

A
  • are hydrophilic <3 and easily dissolved in water
  • like dissolves like
  • polar dissolves polar
  • nonpolar dissolves nonpolar
19
Q

polarity of water molecules:

A
  • makes water a poor solvent (dissolving factor not the sugar)
  • nonpolar substances are hydrophobic (water-fearing)
  • hydrophobic molecules clump together in water bc of hydrophobic interactions
20
Q

oil and water

A
  • oil does not dissolve in water bc the nonpolar oil cannot form hydrogen polar water molecules
  • oil is made up of a lot of H-C bonds (nonpolar no charge)
  • to dissolve it has to form hydrogen bonds w water and to have hydrogen bond w water it has to have charge
  • oil has no charge
21
Q

biomolecules:

A
  • carbohydrates
  • lipids
  • proteins
  • nucleotides
22
Q

carbohydrates:

A
  • monosaccharides (single sugar) contain carbon, hydrogen, and oxygen in a 1:2:1 ratio
  • ring structure
  • purpose: short term energy
  • ex: C6, H12, O6 is a monosaccharide
  • ex: C6, H10, O6 not a monosaccharide
  • disaccharides: 2 sugars
  • polysaccharides: hundreds, thousands of monosaccharides
  • most important is glycogen (energy storage molecule, metabolized when bld sugar levels drop, stored in skeletal muscle and liver)
  • most cells wont store lots of glucose bc water follows into cell via osmosis (when bld sugar is high, glucose gets assembled into glycogen and stored in liver and skeletal muscle)
23
Q

carb-loading

A
  • process of increasing the amount of glycogen stored in the body prior to a race or competition
  • two steps:
  • depletion phase: a week or two prior intense exercise and no-carb/high protein
  • loading phase: a couple of days before no intense exercise, eating many carbs
24
Q

water weight

A
  • bld glucose is metabolized first and after is glycogen, finally fat
  • glycogen is polar (can dissolve in water) each ounce of glycogen has as many as four ounces of water attached to it
  • fat is nonpolar (no water attached to it)
  • slide 30
25
Q

lipids

A
  • lipids consits of nonpolar hydrocarbon chains and rings
  • usually hydrophobic (insoluble in water/ wont dissolve)
26
Q

saturated vs unsaturated

A
  • saturated fats are solid at body temp, have no C=C bonds, saturated with hydrogen bonds (lard, grease, fat)
  • unsaturated are liquid at body temp, at least one C=C bond (olive oil, veg oil) liquid is less-likely to clog arteries
27
Q

cookies

A
  • cookies that are chewy have lots of saturated fats (butter), while cookies that are crunchy have unsaturated fats (veg oil)
28
Q

phospholipids

A
  • two fatty acids + phosphate group attached to glycerol backbone
  • dominant component of cell membranes
  • contains hydrophilic (polar) and hydrophobic (nonpolar) regions
  • phospholipids have heads that dissolve in water and tails that fear water
29
Q

phospholipids and aqueous environment

A
  • makes them ideal for forming cell membranes bc if the whole membrane were water soluble, water would rush right into the cell
  • repel, then nothing would be able to dissolve and cross the membrane
  • thats why they are in a double layer heads facing water all around and tails facing tails preventing water from rushing in and out of cell
30
Q

steroids

A
  • all steroids have the same structure: 4 rings fused together made of cholesterol and most are sex hormones (testosterone and estrogen)
  • three 6 carbon rings + one 5 carbon ring
  • nonpolar
    functions as hormones
31
Q

proteins

A
  • composed of multiple amino acids (amino acid polymers)
  • sequence of amino acids determined by DNA through process of transcription and translation
  • DNA determines the order amino acids are in this is called gene expression (gene instructs cells how to build proteins)
32
Q

amino acids

A
  • composed of amino groups, a carboxyl group and a functional or R group (called sidechain)
  • 20 R groups therefore 20 different amino acids
  • R groups give amino acids different properties (eg. polar or nonpolar)
  • whatever properties found in sidechaine determine properties of the amino acid
33
Q

levels of protein structure

A
  • structure = function
  • all proteins have primary, secondary, and tertiary structure
  • only some have quaternary
  • PRIMARY: order of amino acids
  • SECONDARY: little coil or fold or helix
  • TERTIARY: overall 3 dimensional shape (STRUCTURE IS FUNCTION)
  • QUATERNARY: multiple amino acid chains
34
Q

protein structure

A
  • secondary, tertiary, quaternary contribute to 3D shape of protein
  • 3D is diverse and determines function
  • bc bonds between amino acids and peptides can be weak, proteins can be denatured (broken apart/unfolds) by heat/temp, changes pH, etc.
  • when a protein denatures, its tertiary structure is destroyed
35
Q

nucleotides

A
  • are the letters that make up your DNA (G, A, T, C) and RNA (G, A, C, U)
  • composed of five-carbon sugar, one+ phosphate groups, and a nitrogenous base
  • nitrogenous: two categories
  • pyrimidine: one carbon ring (cytosine and thymine in DNA) think of the letter Y in each
  • purine: two carbon rings (guanine and adenine in DNA)
  • DIFFERENCE: DNA: G A T C, RNA: G A C U, DNA: sugar is deoxyribose (missing an oxygen in the 2nd position that is present in ribose), RNA: sugar is ribose
36
Q

DNA STRUCTURE

A
  • think of book: sugar and phosphate groups are the front and back of book that provide protection
  • the G A T C on the inside are the nitrogenous bases (pages of book) the order of these bases makes DNA unique from others
37
Q

what is a gene?

A
  • a gene is a length of DNA that codes for a specific protein
  • chromosomes are made of DNA and proteins (like a mixture)
38
Q

gene expression

A
  • converting DNA into proteins
  • transcription: DNA –> RNA occurs in nucleus
  • ex: book in library: cant check it out but can copy it
  • translation: RNA –> PROTEIN occurs in cytoplasm (ribosome) where RNA copy is used to make protein
39
Q

transcription

A
  • RNA polymerase binds to promoter (RNA tells polymerase to ‘sit here and start transcribing this gene’)
  • RNA polymerase then unzips DNA, separates double helix (only one strand of DNA is used to make the transcript)
  • free ribonucleotides bind to complementary base on DNA sense strand
  • RNA polymerase moves down the DNA. new RNA molecule is synthesized (G-C/ C-G/ T-A/ A-U) (no thymines in RNA)
  • the pre-mRNA transcript must still be changed slightly before it allowed to leave nucleus
40
Q

genes

A
  • the human genome project revealed hat most of our DNA does not encode mRNAs or any other RNAs. appears to serve no purpose in our life cycle.
  • accounts for 98.5% of chromosomal DNA (junk DNA)
  • these non-coding regions are similar not identical.
  • about 1.5% of our DNA is pretty identical the rest is junk, the rest can mutate often without damaging effects
41
Q

post-transcriptional processing

A
  • pre-mRNA –> mRNA
  • introns are removed
  • CAP is added to 5’ end of the pre-mRNA
  • poly-a tail is added to 3’ end of pre-mRNA
  • pre-mRNA transcription are made of introns (junk/blank pages in a book) and exons (actual coding information)
  • only exons are allowed to exit the nucleus
  • RNA and DNA have 2 distinct ends 5’ end which is the beginning and the 3’ end which is the end
  • a CAP gets added to the 5’ to allow it to exit the nucleus more easily
  • a tail of adenine nucleotides gets added to the 3’ end to allow it to bind to the ribosome easily
42
Q

translation

A

three types of RNA:
- mRNA (made of codons (3 nucleotides/letters in a row)): carries genetic code out of the nucleus
- rRNA (ribosomal RNA): forms RNA components of ribosome (made of rRNA and protein), allows protein assembly
- tRNA (transfer RNA): allows protein assembly (reads the mRNA and brings it to the correct amino acid to build proteins during translation) anti codons are found in tRNA and recognizes and binds to specific codon mRNA

43
Q

human genetic code

A
  • 64 possible codons
  • START: AUG translation begins and it codes for methionine
  • STOP: UGA, UAG, UAA
44
Q

REVIEW 57-64

A

REVIEW 57-64

bio 2160 (10 decks)

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