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UA / Biology / BSC 114 / what is chemical reaction?

what is chemical reaction?

what is chemical reaction?

Description

School: University of Alabama - Tuscaloosa
Department: Biology
Course: Principles of Biology I
Professor: Kimberly caldwell
Term: Fall 2016
Tags:
Cost: 50
Name: BSC Exam 1 Study Guide
Description: Chapters 1-6
Uploaded: 09/18/2016
9 Pages 6 Views 12 Unlocks
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Biology Exam 1


what is chemical reaction?



Chapter 2

∙ Chemical reactions: exchanging and sharing of electrons between  atoms  

∙ Chemical bonds are formed between atoms

∙ Types of bonds

-Covalent

-Ionic

-Hydrogen

Covalent Bonds

∙ Covalent: sharing of a pair of valence electrons between 2 atoms -Electronegativity: attraction of an atom for the electrons of a covalent  bond

-The more electronegative an atom is, the more strongly it will  pull shared electrons toward itself

-Nonpolar and polar covalent bonds share electrons differently ∙ Nonpolar Covalent Bonds (atoms are shared): 2 elements end up being equally electronegative in a bond

-Carbon and Hydrogen nonpolar covalent (They don’t pull  

electrons to themselves) (They are neutral)

∙ Polar Covalent Bonds (atoms are shared): one atom is more  electronegative than the other


what is covalent?



-Electrons will not be shared equally

-Water has unequal sharing so it causes oxygen to have a partial  charge and the hydrogens have a partial positive charge.

Ionic Bonds

∙ Ionic (atoms are transferred): actual loss and gain of electrons -Typically between metal and nonmetal

-Occurs between molecules with opposite charges Don't forget about the age old question of what is the Events in the 1920s leading to neobehaviorism?

-Cation: greater positive charge

-Anion: greater negative charge

Hydrogen Bonds

∙ Hydrogen: a bond between a covalently bonded hydrogen atom and  another atom

-Involves 2 different molecules

-Weakest bond

-Constantly being broken and reformed

Chapter 3

∙ Water molecules form hydrogen bonds with one another ∙ Water increases in volume and becomes less dense when frozen  because of hydrogen bonding

∙ Water is a great solvent

∙ Solvent: the dissolving agent of a solution


what is electronegativity?



∙ Solution: a liquid that is homogenous mix of 2 or more substances ∙ Solute: substance that is dissolved

∙ Only ionic and polar substances will dissolve readily in water ∙ Hydrophobic: substance that is nonpolar and will not dissolve readily in water (oils and fats)

∙ Hydrophilic: water-loving

Chapter 4

∙ Basically everything is carbon-based

∙ Carbon Structure- chains

-Forms skeletons of most organic molecules

-Varies in length, straight, branched, or arranged in close rings -Some have double bonds

∙ Hydrocarbons: organic molecules made of hydrogen and carbon ∙ Isomers: compounds that have the same molecular formula but  different structures and different properties

∙ 3 types of isomers

-Structural

-Enantiomers

-Geometric

∙ Structural

-Differ in covalent arrangements of atoms 

-Number of possible isomers increases as carbon skeletons  increases in size

∙ Enantiomers (3D)

-Mirror images of each other Don't forget about the age old question of Semiotics and related terminology refers to what?

-Cell can distinguish these isomers based on different shapes -Usually one isomer is biologically active and the other is inactive ∙ Geometric  

-Always involves double bonds 

-All have the same partnership but different in their spatial  arrangements

∙ 7 functional groups most important in the chemistry of life -Hydroxyl

-Carbonyl

-Carboxyl

-Amino

-Sulfhydryl

-Phosphate

-Methyl

∙ Hydroxyl group

-found in alcohols

-Polar covalent bond which helps alcohol dissolve in water -Often ends in –ol

-Must have OH

∙ Carbonyl group

-Can be found at the end of carbon skeleton or within a skeleton -Double bonded to oxygen and bonded to hydrogen

∙ Carboxyl group

-Found in carboxylic acids

-Hydrogen in this group can be dissociate, makes molecules a  weak acid

∙ Amino group

-Can accept H+

-Acts as a base

-Can accept H+ and will then be –NH3+

∙ Sulfhydryl group

-Helps stabilize structure of some proteins…… -SH

-Often forms disulfide bridges which are really strong covalent  bonds

- -S-S-

∙ Phosphate group

-Can bond to a carbon skeleton by one of its oxygen atoms -Has important role in transfer of cellular energy (ATP)

∙ Methyl group

-Not reactive like the others, but is a tag that attaches to a bio  molecule

-CH3

-Addition of a methyl group to DNA affects the expression of  genes

-Arrangement of methyl groups in sex hormones affects their  shape and function

Chapter 5

∙ Carbohydrates: sugars If you want to learn more check out what is science?

-Ends in –ose for sugars

∙ 3 types of carbohydrates

-Monosaccharides

-Disaccharides

-Polysaccharides

∙ Monosaccharides

-Molecular formula is some multiple of CH2O

-Has a –OH group attached to the carbon except one, which is  double bonded to an oxygen to form a carbonyl group

-Major nutrients for cells

∙ Disaccharides

-Double sugar

-Consists of 2 monosaccharides joined by a glycosidic linkage (a  covalent bond formed between 2 monosaccharides)

-Most common is sucrose

∙ Polysaccharides

-Polymers of many monosaccharides

-Consists of a few hundred to a few thousand monos linked  together

 Lipids

-2 types: Storage and Structural

∙ Hydrophobic

∙ Mostly composed of hydrocarbon, but have some polar bonds  associated with oxygen 

∙ 3 families of lipids

-Fats

-Phospholipids

-Steroids

Fats

-large molecules constructed from 2 kinds of smaller molecules  Glycerol and fatty acids

 From dehydration reaction

 Glycerol is an alcohol

 Fatty acids are hydrocarbons of 16-18 carbons

-nonpolar C-H bonds in the tails of fatty acids are the reason fats  are hydrophobic

-fats separate from water because the water molecule bonds to  another and exclude fats (like oil and vinegar, 3 fatty acids join to 1 glycerol) If you want to learn more check out What did Gregor Mendel do?

-Saturated fat

 NO double bonds between carbon in the tail We also discuss several other topics like proton donor is what?

 Vary in length and in number and location of double bonds  but saturated fatty acids don’t have double bonds

-Unsaturated fat

 Have one or more double bonds in the tail

 Saturated and unsaturated fats differ in hydrocarbon tails -Trans fats

 What are they?

o Partially hydrogenated fats

o Less vulnerable to becoming rancid than original oils  (going bad)

Phospholipids

-main component of our cell membrane  

-structurally related to fats

-only has 2 fatty acid chains instead of 3 and has a phosphate  group (on 3rd glycerol)

-PO4 group is negatively charged

-sometimes other small molecules that are charged or polar can  be linked to a phosphate group to form a variety of phospholipids -Phospholipids in cells If you want to learn more check out What is a coaching code of ethics?

 At the surface of a cell the phospholipids are arranged in  double layer (bilayer)

 Hydrophilic head: on outside of bilayer

 Tails pointed toward interior of membrane, away from  

water

Steroids

-carbon skeletons consisting of 4 interconnected rings 

∙ Proteins

∙ Account for more than 50% of dry weight of cells

∙ Structurally complex but comprised of amino acids

∙ Consists of  

-Alpha carbon bonded to a hydrogen

-Carboxyl group

-Amino group

-Side chain symbolized by R

∙ Amino Acids

∙ Processing both carboxyl groups

∙ Identification of Amino Acid Type

-Nonpolar R groups will share electrons equally (typically  

composed of hydrocarbon)

-Polar R groups: electrons will not be shared equally (possess  functional groups like OH and SH)

-Acidic: these R groups contain carboxyl groups (COOH)

-Basic: these R groups contain amino groups and have N+  Does not have oxygen associated in the R group

∙ Amino Acids are linked to for protein polymers

∙ Condensation synthesis

∙ The carboxyl group of amino acid is joined to the amino group of  another  

∙ 4 levels of a protein structure

-Primary

-Secondary

-Tertiary

-Quaternary

Primary

∙ Unique sequence of amino acids of a protein

∙ This protein transports vitamin A in our blood

Secondary

∙ The folding of a polypeptide chain due to hydrogen bonds at regular  intervals along polypeptide backbone or skeleton

∙ 2 types

-Helix

-Pleated sheets

∙ Secondary structure is protein dependent

Tertiary

∙ Bonding between side chains (R groups) of the various amino acids ∙ R chains provide tertiary structure

-Hydrophobic interactions: nonpolar side chains usually cluster at the core of the protein (out of contact with H2O)

-Hydrogen bonds between tertiary structure

-Ionic bonds between positively and negatively charged side  chains

-Disulfide bridges (strong covalent bonds) form when 2 cysteine  monomers are brought close together by the folding of the  protein

Quaternary

∙ Interaction of more than one polypeptide chain (or subunit) ∙ Some proteins consist of more than one polypeptide chain

∙ Nucleic Acids: store, transmit, and help express heredity information ∙ The amino acid sequence of a polypeptide is programmed by a unit of  inheritance called a gene 

∙ Genes consist of DNA, a nucleic acid made of monomers called  nucleotides 

∙ 2 types of nucleic acids

-Deoxyribonucleic acid (DNA)

-Ribonucleic acid (RNA)

∙ DNA provides directions for its own replication

∙ Gene expression: DNA directs synthesis of messenger RNA (mRNA)  and, through mRNA, controls protein synthesis

∙ The flow of genetic information: DNARNAProtein

∙ Nucleic acids are polymers called polynucleotides 

∙ Each polynucleotide is made of monomers called nucleotides ∙    Each nucleotide consists of a nitrogenous base, a pentose sugar, and  one or more phosphate group 

∙ The portion of a nucleotide without a phosphate group is called a  nucleoside

∙ Nucleoside=nitrogenous base + sugar

∙ 2 families of nitrogenous bases

-Pyrimidines have a single 6-membered ring

-Purines have a 6-membered ring fused to a 5-membered ring ∙ Nucleotide=nucleoside + phosphate group

∙ DNA molecules have 2 polynucleotides spiraling around an imaginary  axis, forming a double helix

∙ The backbones run in opposite directions from each other, an  arrangement referred to as antiparallel 

Chapter 6

Cells

∙ The lowest level structure capable of performing all the activities of life ∙ Known as cytology or cell biology 

Prokaryotes

∙ Bacteria  

∙ Simple structure

∙ No membrane-enclosed organelles

∙ Has NO nucleus

∙ DNA is concentrated in a region called nucleoid but no membrane  surrounds it 

∙ The study of bacteria=microbiology 

Eukaryotes

∙ All life forms except bacteria

∙ Includes plants, fungi, and animal cells

∙ True karyon (or nucleus), indicates the nucleus is enclosed by a  membrane 

∙ Possess membrane-bound organelles

∙ Typically, 10X bigger than bacteria  

Prokaryotes vs. Eukaryotes

∙ Prokaryotes

-No nucleus, just a region in the cell containing DNA (called  nuclei)

-No membrane-bound organelles but has plasma membrane and  ribosomes

∙ Eukaryotes

-Nucleus

-Variety of organelles  

-Organelles have membranes

Plant vs. Animal Cells

∙ Most organelles are found in both plant and animal cells ∙ Animal cells have the following organelles that plant cells do NOT have -Lysosomes

-Centrioles

-Flagella

∙ Plant cells have the following organelles that animal cells do NOT have -Chloroplasts

-Central vacuole  

-Cell wall plasmodesmata

Nucleus

∙ Contains most genetic material of cell

∙ Its enclosed by the nuclear envelope  

-The nuclear envelope is a double membrane with pores for the  passage of certain macromolecules.

∙ Within the nucleus our DNA is organized with protein into chromatin  that looks like a stringy mess with a microscope.

∙ Chromatin condenses into chromosomes before cell division Nucleolus

∙ Site of synthesis and assembly of the components of ribosomes ∙ Ribosome components then pass through the nuclear pores to the  cytoplasm where they combine to form ribosomes

Ribosomes

∙ Site of protein synthesis  

∙ 2 types of ribosomes

-Free ribosomes-suspended in the cytoplasm

 They make proteins that function within the cytoplasm.

-Bound ribosomes-attached to the ER

 They generally make proteins that are parts of membranes  or to be exported from the cell.

Endoplasmic Reticulum (ER)

∙ Endoplasm=cytoplasm; reticulum=network

∙ A membranous network within the cytoplasm

∙ Consists of membranous tubules and sacs called cisternae  ∙ The ER membrane separates its internal compartment from the cytosol ∙ The ER is also continuous with the nuclear envelope

∙ 2 types of ER

-Smooth

-Rough

Smooth ER

∙ Cytoplasmic surface lacks ribosomes

∙ Functions in  

-Lipid synthesis (fats, phospholipids, steroids)

-Calcium ion storage in muscle cells

Rough ER

∙ Cytoplasmic surface of ER membrane is studded with ribosomes ∙ Functions in the final steps of synthesizing membrane proteins ∙ Proteins are folded into their native states within the ER Golgi Apparatus

∙ It is the center of  

-Manufacturing

-Sorting

-Warehousing

-Shipping

∙ One side of Golgi receives transport vesicles from the ER and then  ships material out from its trans face

∙ The cis face is usually located near ER 

∙ Protein products are modified while traveling inside Golgi, from the  receiving to the shipping end

Lysosomes

∙ Membrane-enclosed bag of hydrolytic enzymes

∙ Cell uses lysosomes to digest macromolecules and part of damaged  cells

∙ Membranes are important in lysosomes, otherwise the hydrolytic  enzymes would digest otherwise healthy cells  

Lysosome Functions

∙ Phagocytosis: process of engulfing food particles  

-Performed by amoebas and in some human cells as well ∙ Autophagy: recycling the cell’s own organic material

-Lysosome engulfs another organelle (human liver does this  often)

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