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UB / Biology / BIO 201 / What happens when acids dissolve in water?

What happens when acids dissolve in water?

What happens when acids dissolve in water?

Description

School: University at Buffalo
Department: Biology
Course: Cell Biology
Professor: R. shortridge
Term: Spring 2018
Tags: Biology and cellular biology
Cost: 50
Name: BIO201 Study Guide for Exam 1
Description: This is a study guide for the first exam for BIO201.
Uploaded: 02/15/2018
6 Pages 37 Views 3 Unlocks
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BIO201 Study Guide for Exam 1


What happens when acids dissolve in water?



Lecture 2: 

Chapter 2: Introduction to Biological Chemistry 

o All matter is composed of atoms comprised of protons,  neutrons, and electrons

o Atomic number=# of protons

o Mass number=# of protons + # of neutrons

o The outermost electron shell (valence shell) determines how  the atom behaves

o Chemical bond: the attractive force that links atoms together to form molecules

Lecture 3: 

Ions-electrically charged particles formed when atoms lose or gain electrons

Cations-positive

Anions-negative

Complex ions: groups of covalently bonded atoms that carry a  charge


What is another name for simple sugars?



Hydrogen bonds: attraction between the partial negative end of one molecule and the partial positive hydrogen end of another  molecule

o Hydrogen bonds form between water molecules and are  important in the structure of DNA and proteins

o Polar molecules that form hydrogen bonds with water are  hydrophilic (water-loving) Don't forget about the age old question of Which elements organize the universe?

o Nonpolar molecules, such as hydrocarbons that  interact with each other but not with water are  

hydrophobic (water-hating)

Van der Waals forces: attractions between nonpolar molecules  that are close together

o Individual interactions are brief and weak, but can be  substantial when summed over a large molecule


Why does protein shape change sometimes?



Don't forget about the age old question of What does a free-body diagram show?

Mole: The amount of a substance (in grams) that is numerically  equal to its molecular weight

o The number of molecules in 1 mole is constant for all  substances

o One mole contains 6.02 x 1023 molecules=Avogadro's  number Don't forget about the age old question of What kinds of protein are found in plasma membrane?

A 1 molar solution (1M) is 1 mole of a substance dissolved in  water to make 1 liter of solution If you want to learn more check out How to calculate nominal and real gdp when given data on output in various industries and prices in those industries?

o In living tissues, substances occur in micromolar, and  smaller, concentrations

When acids dissolve in water, they release hydrogen ions (H+ protons)

o H+ ions can attach to other molecules and change their  properties

o Bases accept H+ ions

HCl is a strong acid; it fully ionizes in water Don't forget about the age old question of Where does acetylcholine come from?

NaOH is a strong base (it accepts H+)

pH-negative log of the molar concentration of H+ ions o Lower pH numbers means higher H+ concentration, or  greater acidity

Chapter 3: Amino acids, proteins, carbohydrates, and  lipids 

Molecules that make up living organisms:

o Proteins

o Carbohydrates

o Lipids

o Nucleic acids

o Most are polymers of smaller molecules called  monomers

Proteins: combinations of 20 amino acids

o Polypeptide chain: single, unbranched chain of amino  acids

o Proteins consist of one or more polypeptide chains, which  are folded into specific 3-D shapes defined by the  sequence of amino acids We also discuss several other topics like What are examples of elementary matrices?

o Amino acids have carboxyl and amino groups-they  function as both acid and base

Carbohydrates: sugar monomers (monosaccharides) are linked  to form polysaccharides

 Monosaccharides: simple sugars

 Disaccharides: two simple sugars linked by covalent  bonds

 Oligosaccharides: 3 to 20 monosaccharides

∙ May include other functional groups

∙ Often covalently bonded to proteins and lipids on  cell surfaces and act as recognition signals

 Polysaccharides: hundreds or thousands of  

monosaccharides

∙ Giant polymers of monosaccharides

∙ Starch-storage of glucose in plants

∙ Glycogen-storage of glucose in animals

∙ Cellulose-very stable, good for structural  

components

o Have the general formula: CmH2nOn

o Sources of stored energy

o Used to transport stored energy

o Carbon skeletons for many other molecules

Nucleic acids: four kinds of nucleotide monomers o Polymers specialized for the storage, transmission, and  use of genetic information

o Said to grow in the 5'-to-3' direction

 DNA=deoxyribonucleic acid

∙ Contains deoxyribose

∙ Two strands of a DNA molecule form a double  helix

∙ DNA is an informational molecule: information is  encoded in the sequences of bases

∙ Can reproduce itself (replication)

∙ Sequences can be copied into RNA  

(transcription)

∙ The RNA can specify a sequence of amino acids in  a polypeptide (translation)

Transcription plus translation=expression

 RNA=ribonucleic acid

∙ Contains the sugar ribose

o Nucleotides-monomers that make up nucleic acids  Consist of a pentose sugar, a phosphate group, and a  nitrogen-containing base

 Nucleotides are linked together in condensation  

reactions to form phosphodiester linkages

∙ Nucleoside-consists only of a pentose sugar and  a nitrogenous base

o Oligonucleotides- about 20 monomers, RNA "primers" to start DNA duplication. RNA that regulates gene  

expression, etc.

Complimentary base pairing: purines pair with pyrimidines by hydrogen bonds

Other roles for nucleotides:

ATP-energy transducer in biochemical reactions

GTP-energy source in protein synthesis

cAMP-essential to the action of hormones and transmission of  information in the nervous system

Lipids: noncovalent forces maintain interactions between lipid  monomers

o Nonpolar hydrocarbons insoluble in water

o If close together, weak but additive van der Waals forces  hold them together

o Not polymers in the strict sense because they are NOT covalently bonded

o Fats and oils store energy

 Phospholipids-structural role in cell membranes

 Carotenoids and chlorophylls-capture light energy in  plants

∙ Carotenoids-light-absorbing pigments

 Steroids and modified fatty acids-hormones and  vitamins

∙ Steroids-multiple rings share carbons

∙ Cholesterol is important steroid in  

membranes; other steroids function as  

hormones

 Animal fat-thermal insulation

∙ Lipid coating around nerves provides electrical  insulation 

∙ Oil & wax on skin, fur, and feathers repels water

Lecture 4: 

∙ The terminal -SH group of cysteine can react with another  cysteine side chain to form a disulfide bridge/bond,  important in protein folding

α helix-right-handed coil resulting from hydrogen bonding  between N-H groups on one amino acid and C=O groups on  another

β pleated sheet-two or more polypeptide chains are aligned;  hydrogen bonds form between the chains

Proteins bind noncovalently with specific molecules determined  by:

∙ Shape-there must be a general fit between the 3-D shapes  of the protein and the other molecule

∙ Chemistry-R groups on the surface interact with other  molecules via ionic, hydrophobic, or hydrogen bonds

Conditions that affect secondary and tertiary structure: 1 High temperature

2 pH changes

3 High concentrations of polar molecules

4 Nonpolar substances

Protein shape can change as a result of:

1 Interaction w/ other molecules (an enzyme changes shape  when it comes into contact w/ a reactant

2 Covalent modification-addition of a chemical group to an  amino acid

Chaperones-proteins that help prevent other proteins from  binding to the wrong molecules after denaturation or when they  are newly made and still unfolded; allows denatured protein to  refold

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