Transcript Intro to Biology & Biochemistry

Intro to Biology &
Biochemistry
Ch. 1 & 2
 Biology
- study of living things
Organism– complete, individual living
thing
Characteristics of Living Things

1. All organisms are made of cells - these are
the basic building blocks (smallest unit that
can carry on the activities of life)
unicellular – organism composed of a single
cell (bacteria)

multicellular– more than 1 cell (humans)

2. Organisms are
highly organized – the
basic difference
between organisms is
the way they
synthesize raw
materials– cells are
like miniature
factories. Living
things are based on a
universal genetic
code.
Organisms use energy – the ultimate
source of energy is sunlight – Plants
typically store excess energy as oils while
animals typically store excess energy as
fats
 Metabolism– sum of chemical building up
(anabolism) & breaking down
(catabolism)
 3.
Organisms grow & develop – growth is
increasing in size while development is
maturation.
 4.
 5.
Organisms have a life span (average
length of life) & all organisms maintain a
stable internal environment – this is called
homeostasis.
 6.
Organisms reproduce– this is
necessary for the continued existence of
the species. In sexual reproduction, 2
cells from different parents unite to
produce the first cell of the new organism
(offspring & parents have different
traits). In asexual reproduction, the new
organism has a single parent (offspring &
parents have the same traits).
 7.
Organisms respond to a stimulus - this
is any condition to which an organism can
react; the resulting action is called a
response; irritability refers to the ability
to respond to stimuli
 8.
Organisms adjust to their
environment– one must adapt to survive
– any change in an organism that makes it
better suited to its environment is an
adaptive response. Variation refers to a
set of differences among individuals –
sometimes these variations may give the
organism an edge over others. Any kind
of organism can change, or evolve over
time.
The Scientific Method – a logical,
organized method of study

1. State the problem

2. Collect
information (use all
available sources –
library, internet,
magazines,
interviews)
 3.
Formulate a
hypothesis – a
statement that can
be tested. It should
be short, definitive, &
positive.

4. Experiment. This
involves testing the
hypothesis. A variable is
a condition that changes
in the experiment.
 Independent variables
may be controlled by the
experimenter. These
belong on the x-axis of a
graph.
 Dependent
variables are typically the
results. These belong on the y-axis of a
graph. A controlled experiment is one in
which there is only 1 experimental variable
(all of the conditions are alike except for
the one being tested). The experimental
group is exposed to the experimental
variable while the control group is not. In
scientific experiments, only one variable is
changed at a time.
 5.
Make & record observations. This
includes data, statistics, graphs, etc.
Quantitative observations involve
numbers – counting or measuring
objects. Qualitative observations involve
characteristics that can’t be counted – ex.
= color, texture, etc.
 6.
Draw a conclusion. This may or
may not support the original
hypothesis.
Redi’s Experiment with
Spontaneous Generation
Spallanzani’s Experiment
Pasteur’s Experiment
A
scientific law explains how an event
occurs while a scientific theory explains
why an event occurs. It is a well-tested
explanation that unifies a broad range of
observations.
An inference is a logical interpretation
based on prior knowledge & experience.
Examples
Observations
Inferences

The dog’s tail is
wagging


The man is riding a
bicycle


The Braves are leading
the wild card

The dog’s tail is
wagging because he is
excited.
The man is riding a
bicycle because his car
won’t start.
The Braves are leading
the wild card because
they are playing well
right now.
Observation vs. Inference
Statement
Observation Inference
Object A is round and orange.
X
X
Object A is a basketball.
Object C is round and black and white.
Object C is larger than Object B.
Object B is smooth.
X
X
X
Object B is a table-tennis ball.
Each object is used in a different sport.
X
X
X
Observation vs. Inference
 Microscopes
are used to study
cells. Magnification refers to the ability to
make an image larger. Resolution refers
to the ability to show details clearly. As
magnification increases, resolution
typically decreases.
Types of Microscopes
 1.
Compound light- uses light
passing through 1 or more
lenses to produce an image –
produce magnified images by
focusing visible light rays - (we
use these at school) –
Magnification = multiplying the
magnifications of the lenses
 2.
Electron microscopes - these produce
magnified images by focusing beams of
electrons
a. Transmission e- microscopes – produces a
stream of electrons that passes through a
specimen – thinly sliced, then stained – used to
view internal structure – magnifies up to 200,000x
 b.
Scanning emicroscopes –
beam of electrons
reveals surface
details of images –
gives 3-D
appearance –
specimens are
coated with metal magnifies up to
100,000x
BIOCHEMISTRY
 Atoms
- are the building blocks of matter
– They are made of protons (positive
charge), electrons (negative charge), &
neutrons (no charge). Because the
number of protons equals the number of
electrons, atoms have a neutral
charge. The protons & neutrons make
up the nucleus of an atom.
 Elements
- are pure substances that are
made of only 1 type of atom.
Molecules - are the smallest particles that
can have a stable, independent existence
– they are typically joined by covalent
bonds.
Compounds - are groups of atoms held
together in definite proportions by
chemical bonds
Isotopes - are atoms of the same element
that differ in the number of neutrons they
contain – they still have the same number
of protons.
Isotopes
Chemical Bonds
 All
atoms strive for a stable octet
 1) Covalent bonds- when atoms share
electrons – these are very strong;
Example = O2, H2O
2) Ionic - molecules have opposite
charges & transfer electrons – these
dissociate in water ; Example = NaCl
Ionic Bonding
INTERMOLECULAR FORCES:

3) Hydrogen bonds- weak
bonds – can’t form with long
distances – these link
molecules rather than
atoms; Example = between
the bases of DNA
4)Van der Waals forces slight attraction that
develops between the
oppositely charged regions
of nearby molecules - holds
molecules together

Organic compounds are made by living things &
contain the element carbon.
Inorganic compounds are not made by living
things.

The elements that are crucial for life are C
HOPKINS Ca Fe.
The elements that are considered
macromolecules are CHOPSN.

Water is the most important
inorganic compound for living
things. Most cellular activities take
place in its presence. Water is a
neutral molecule (positive charges
balance the negative
charges). Water is a polar molecule
because there is an uneven
distribution of electrons between the
oxygen & hydrogen atoms. Drawing:
Characteristics of water:

1. High heat capacity (this means it can
absorb & release great amounts of heat before
changing its temperature)
2. Cohesion (this means it clings to itself – this
creates surface tension)

3. Adhesion (this means it clings to other
molecules – this creates capillary action)

4. Water ionizes
(when the covalent
bonds break, a
hydrogen ion and a
hydroxide ion are
produced)
5. Universal solvent
(this is because it is a
polar molecule)

A mixture is a material composed of 2 or more
elements or compounds that are physically
mixed together but not chemically
combined. The 2 parts of a solution are the
solute (the substance being dissolved) & the
solvent (the substance in which it is dissolved).
ACIDS & BASES
 Acid
- any compound that forms
hydrogen ions when dissolved in water –
proton donors, electron acceptors,
increase {H+}, turns litmus paper red,
found below 7 on the pH scale; Example
= sulfuric acid

Base - any compound
that forms hydroxide
ions when dissolved
in water – turns litmus
paper blue, found
above 7 on the pH
scale; Example =
bleach

The pH scale’s range
is from 0 14. Neutral is 7. The
pH scale is a
logarithmic scale
meaning it increases
or decreases in
powers of 10.
ORGANIC COMPOUNDS
 Carbon
is the backbone of all organic
molecules. It can bond with other Carbons
to form rings or chains. Carbon prefers to
have 4 bonds.
Monomers are basic units that repeat
themselves. When 2 or more of these
combine, a new compound is formed
called a polymer.

A condensation
reaction is the process
of joining monomers
to build polymers. In
the process, 2
hydrogens, and 1
oxygen are released &
these form water.

A hydrolysis reaction
is the process of
breaking down
polymers into
monomers. Water is
necessary for this
reaction to occur.
There are 4 Classes of Organic
Compounds.

1)Carbohydrates
 2)Lipids
 3)Proteins
 4) Nucleic Acids
CARBOHYDRATES
 Living
things use carbs as their main
source of energy
-contain the elements C, H, & O in a
ratio of 1:2:1, meaning that if there are 6
Carbon atoms, there will be 12
hydrogen atoms & 6 oxygen atoms
- examples of carbohydrates are
starches, sugars, & glycogen
- they are mainly used as structural or
energy storage molecules
- are sugars that can’t
be hydrolyzed into smaller units examples are glucose, galactose,
fructose - Their formula is C6H12O6.
 They are all isomers of each other (they
have the same chemical formula but
different structural formulas)
 Monosaccharides





Disaccharides - result
from the condensation
of 2 monosaccharides
Examples are
sucrose = glucose +
fructose
lactose = glucose +
galactose
maltose = glucose +
glucose
Polysaccharides 1000’s of sugars
combined; examples
are starch, glycgen &
cellulose
Sugar
Sweetness
fructose
173%
sucrose
100%
glucose
74%
maltose
33%
galactose
33%
LIPIDS

- examples are fats,
oils, & waxes - they
contain the elements
C, H, & O and consist
of the monomers
glycerol + 3 fatty
acids
- all are insoluble in
water because they
are nonpolar
compounds
- they are used for the
storage of energy & in
hormone/steroid
 Saturated
fats contain all single bonds &
are difficult for the body to break down.
Unsaturated fats contain more double
bonds & are easier for the body to
attack. These are healthier for the
body. These fats can be made saturated
by hydrogenation such as in Crisco (trans
fats).
Lipases are enzymes that break down fats
& oils.
Lipids are essential for the body for cell
membranes, cushioning, hormone
synthesis.
PROTEINS

- the basic building blocks
for the body
- they contain the
elements C, H, O, N, &
sometimes S- they are
made of monomers
known as amino acids
- polypeptides are long
chains of amino acids
- proteins are held
together by peptide
bonds

The 2 classes of proteins are
1) Structural - these make
hair, nails, ligaments, &
tendons; &
 2) Dynamic - these make
things happens & include
enzymes & hemoglobin
Proteins have a native
configuration – this is their
original shape. Most proteins
that are denatured cannot be
annealed.
 Enzymes
are proteins that act as
catalysts(speed reactions). They lower
the activation energy but are not used up
in the reaction. They are specific (think
key & lock). The substrate is what the
enzyme acts on. The active site is where
the enzyme & substrate come into
contact. Coenzymes help enzymes bind
to the substrate (vitamins). Inhibitors
slow or stop enzyme activity by either
blocking the active site or distorting the
enzyme’s shape.
NUCLEIC ACIDS

- these carry instructions for cellular activities –
they store hereditary info to make protein
- nucleic acids are made from the monomers of
nucleotides- these are made of 1) a nitrogen
base (adenine, thymine, guanine, uracil, &
cytosine), 2) a 5-C sugar, & 3) a phosphate
group.

The 2 nucleic acids
are DNA & RNA.
DNA is found in the
nucleus & records
instructions. RNA is
found in the nucleus
& cytoplasm & reads
instructions & carries
them out.