Biology CHP 2-5

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updated 13 days ago by cocordrgz
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1

Element

Substance cannot be broken down

defined by proton #

2

Compound

2/more elements together in specific ratio

3

Atom

smallest unit of matter w/ properties of the element

4

Reading elements

Atomic # = # protons

mass # = protons + neutrons

atomic mass = atom's total mass

5

Energy levels

potential energy = energy smth has bc of location / height

-shells of atom > more potential energy as valance electrons farther

6

Ionic bonds

-More electronegative atom strip needed electrons from other

  • Electron transfer

Interaction btw anion / cation

-any 2 elements of opposite charge can bond (transfer of electrons not actually required)

7

Covalent bonds

-Sharing of electrons by 2 atoms

-Electronegativity - atom's attraction for electrons in covalent bond

  • nonpolar - electrons shared equally
  • polar - 1 atom more electronegative = unequal sharing

= partial pos/partial neg charges on both (EX: H2O)

8

Hydrogen bonds

-H atom in covalent bond is attracted to other electroneg atom

-Usually O or N

>H is partially pos bc bonded to electroneg atom already = it wants to join another electroneg atom

9

Properties of water

1. Cohesive behavior

  • Hydrogen bonds btw water molecules hold them together = surface tension > difficult to break surface
  • = how water is pulled up in plants
  • adhesion - between 2 different molecules (H in water to cell wall = pull up)
  • cohesion - btw 2 of same molecules

2. Ability to moderate temperature

  • water absorbs heat from warm air + release stored heat in cool air

3. Expansion upon freezing

  • frozen H bonds form hexagon = more space

4. Versatility as solvent

5. Van der waals interactions

  • electrons not equally distributed > accumulate in 1 part of molecule by chance at a given instant
  • many at once can = powerful
  • (EX: gecko climbing wall)
10

Hydrocarbon

-molecules = only C + 4H

=stored energy

-in fat

11

Isomers

-structure w/ same molecular formula > diff structure + properties

*structure determines properties*

structural isomers - diff covalent arrangement of atoms

cis-trans isomers - same covalent bonds, differ in spatial arrangement

  • due to 2x bonds (dont rotate like 1x bonds)
  • spatial arrangement differ around 2x bond

Enantiomers - isomers that are mirror images

  • Left hand, right hand
  • important in pharmaceuticals
  • 1 usually = only biologically active one
12

Functional groups

card image

***All except sulfhydyl hydrophilic = soluble in water

hydroxyl (-OH) - polar bc O = high electroneg + alcohol group on end

carbonyl (>C=O) - O= electroneg

  • sugars w/ ketone (in molecule) = ketoses
  • sugars w/ aldehyde (at end of molecule) = aldoses

Carboxyl (-COOH) - act as acid

Acid = proton donor

Base = proton acceptor

Amino (-NH2) - act as base (+ proton)

Sulfhydryl (-SH) - 2 of same group react ("cross-link") >stabilize protein structure

Phosphate (OPO3 2- ) - add neg charge > ability to react w/ water = release energy (***ATP)

Methyl (-CH3) - affect gene expression > shape/function of sex hormone

- not reactive, serve more as tag

13

Monomers/polymers

Polymer - chain of monomers

  • proteins, carbs, nucleic acids

Monomers - building blocks of polymers

  • amino acids, simple sugars, nucleotides
14

terms for sugars

carbohydrate = complex sugar

  • starch, glycogen, etc)
  • storage/building material

monosaccharide - base unit of carbs (monomer)

  • multiples of simple sugars (CH2O)
  • Glucose = C6H12O6
  • aldose/ketose monosaccharide determined by location of carbonyl group

polysaccharide - polymer of monosaccharides (polymers)

15

monosaccharides

card image

Trioses - 3 carbon sugars (C3H6O3)

  • Aldose (aldehyde, carbonyl group on END of skeleton)

>Glyceraldehyde

  • Ketoses (ketone, carbonyl within)

>Dihydroxyacetone

Pentoses - 5 carbon (C5H10O5)

  • Aldose > Ribose
  • Ketose > Ribulose

Hexoses - 6 carbon (C6H12O6)

  • Aldose > Glucose, Galactose (differ in cis/trans hydroxyl)
  • Ketose > Fructose
16

Disaccharides

double sugar (2 monomers)

-joined by dehydration rxns

  • covelent bond = glycosidic linkage
17

Macromolecules

polymers build from monomers

18

Enzymes

macromolecules that speed rxns

19

Dehydration

2 monomers bond thru loss of water molecule

20

Hydrolysis

separation (bond break) + use a water molecule in process

-catalyzed by enzymes

21

Storage polysaccharides

-Plants

  • starch > glucose monomers, store extra starch in chloroplasts
  • mix of amylose (single strand)
  • and amylopectic (branched)

-Animals

  • Glycogen (more branched)
  • glucose monomers arranged /attached differently
  • hydrolysis of glycogen > release glucose when needed
  • stored a lot in liver + muscle cells
  • branches allow for faster use when needed (energy > blood)
22

Structural polysaccharides

-Plants

  • Cellulose - walls of plant cells, polymers of glucose
  1. -glycosidic linkage of cellulose = 2 possible rings (alpha and beta > cis trans)
  2. plant cell wall = many tubes of cellulose microfibrules attached by H bonds btw them)
  • Chitin - structural support
  1. exoskeletons
  2. cell wall in fungi
23

Lipids

-large bio molecules dont include polymers

-too small to be macromolecules

-Hydrophobic (mainly hydrocarbons = non polar)

-fats phospholipids, steroids

-store fuel

24

Fats

-Made of 1 glycerol + 3 fatty acids

  • glycerol - 3 carbon alcohol + hydroxyl on each
  • fatty acid - carboxyl group attached to long carbon skeleton
  • nonpolar hydrocarbons = hydrophobic

-Triglyceride (fat molecule)

  • 3 fatty acids + 1 glycerol
  • join thru dehydration
  • bond = ester linkage

-unsaturated fatty acid

  • 1/more 2x bonds
  • kink = cant pack tightly
  • LIQUID at room temp
  • cis 2x bond
  • fish, plants

-saturated

  • no 2x bonds
  • packed closely
  • solid toom temp
  • animals (EX: butter)

-hydrogenated fats

  • converted unsaturated > saturated
  • by adding hydrogens
  • = transfats - unsaturated fats w/ trans 2x bond
25

Fats-Phospholipids

-2 fatty acids + phosphate group + glycerol

-head=glycerol + choline + phosphate

  • hydrophylic bc phosphate ionized

-self assemble BILAYER in water

26

Fats-steroids

-lipids w/ skeleton of 4 fused rings

cholesterol -animal membrane, fluidity