Chemistry is life
• Molecules make up components of cells
• Four major organic molecule types:
1.
2.
3.
4.
Carbohydrates (sugars, starches)
Lipids (fatty acids)
Proteins
Nucleic acids (DNA, RNA, ATP)
1. Carbohydrates
•Carbon + Hydrogen +
Oxygen
•Ex. sugars/starches
•composed of single sugar
units called
monosaccharides, ex.
glucose.
•can bond to form more
complex compounds like
table sugar, ex. sucrose (1
glucose + 1 fructose); 2 sugar
units=disaccharide.
C
C
C
C
C
C
glucose
C
C
C
C
C
Carbohydrates
•Some important CHO’s are:
–glycogen (how animals store food)
–starch (how plants store food)
–cellulose (plant cell wall compound)—most
common CHO on planet
–chitin (shells of bugs and some cells in fungi)
2. Lipids (Fats)
•Usually made of fatty acids and a
molecule called glycerol
•fats are either saturated or unsaturated
•saturated fats, like lard, are the worst for
humans
•unsaturated fats, like fish oils and plant
oils, are better, and can be bonded
together to make more complex fats
called polyunsaturated fats.
Lipids/Fats (cont.)
•Lipids are extremely
important: cell
membranes
•lipids make other
molecules like
hormones (estrogen,
testosterone)
•Ex.cholesterol is a lipid
byproduct used to make
hormones
The cell membrane is a fluid mosaic
of phospholipids and proteins
Fibers of the
extracellular
matrix
Carbohydrate
(of glycoprotein)
Glycoprotein
Glycolipid
Plasma
membrane
Figure 5.12
Phospholipid
Microfilaments
of cytoskeleton
Cholesterol
Proteins
Cytoplasm
3. Proteins
•Composed of units called
amino acids
•only 22 amino acids exist,
with 20 used for amino acids
•all share a similar structure
•amino acids form a peptide
bond or sulfur bond with
others
•as these chains of peptides
form, they either form a spiral
or a flattened sheet.
Amino acid
3. Proteins
•protein spirals or
sheets form
complicated
compounds
•Ex. hemoglobin in
your red blood cells
that carry oxygen:
Hemoglobin
How proteins fold to become more complex proteins:
Modified proteins: enzymes
•Enzymes are amazing!
•Modified proteins
•Names end in –ase
ex. Glucose is sugar, glucase is enzyme that breaks it
down
ex. Amylose is starch, amylase is enzyme
•Speed up chemical reactions
•Break compounds apart
•Put compounds together
Enzymes can break apart molecules OR put them together!
How enzymes work
•Two models: lock&key or induced fit
•Lock&key: exact fit of compounds to
enzyme
•Induced fit: enzyme can “wrap” around
compounds
4. Nucleotides
•3 parts
•1. phosphate
OH
molecules
(phosphorus + O P
oxygens)
O
Phosphate
•2. a sugar
group
•3. a base that
contains nitrogen
H
H
N
N
N
H
N
O
CH2
Nitrogenous
base (A)
O

H
H
H
H
OH
Sugar
N
H
H
Examples of Nucleotides:
•DNA (deoxyribonucleic acid)—holds genetic
information
•RNA (ribonucleic acid)—takes information from
DNA and makes proteins
•ATP (adenosine triphosphate) is important in
transferring electrons; major energy carrier for
cells
ATP uses Electrons to store/release energy
– In living organisms, chemical energy is stored by using
it to move electrons to more distant orbits.
– ATP powers nearly all forms of cellular work
– The energy in an ATP molecule lies in the bonds
between its phosphate groups
Adenosine
Adenosine diphosphate
Triphosphate
Phosphate
groups
P
Adenine
P
H2O
P
P
Hydrolysis
Ribose
ATP
Figure 5.4A
ADP
P
+
P
+
Energy
Structure of DNA
Nucleotide = N-containing base, a pentose sugar, and a
phosphate group
Five nitrogen base types – adenine (A), guanine (G), cytosine
(C), thymine (T), and uracil (U)
Figure 2.21a
Molecules make Cells possible:
•
•
•
•
•
Sugars for energy
Proteins for building structures
Lipids for cell membranes
DNA/RNA for making more cells
ATP for making energy possible
Molecules make Cells possible:
•
•
•
•
•
Sugars for energy
Proteins for building structures
Lipids for cell membranes
DNA/RNA for making more cells
ATP for making energy possible
Prokaryotes vs. Eukaryotes
•DNA in single loop
•Very small
•No organelles
•Live in all environments
•DNA in chromosomes in
nucleus
•Much larger
•Organelles handle
complex cell tasks
•Live in restricted
environments
Prokaryotic cells are structurally simpler than
eukaryotic cells
Prokaryotic cell
Colorized TEM 15,000 
Nucleoid
region
Nucleus
Figure 4.3A
Eukaryotic cell
Organelles
Surface Area to Volume Ratio
A small cell has a greater ratio of surface area to volume
than a large cell of the same shape
10 m
30 m
30 m
Figure 4.2B
Surface area
of one large cube
 5,400 m2
10 m
Total surface area
of 27 small cubes
 16,200 m2
Eukaryotic cells—plants, fungi,
animals, protists
• Nucleus
present
• Membrane
surrounds cell
• Cell wall may
be present
(plants, fungi,
but NOT
animals)
Plasma membrane
• Surrounds entire cell
• Made of two lipid layers
• Allows certain molecules in/out =
“selectively permeable”
Nucleus—control center
Cytoskeleton—internal ‘skeleton’
Internal membrane system
3 important
membranes:
1.
Rough endoplasmic
reticulum
2.
Smooth
endoplasmic
reticulum
3.
Golgi complex
•Smooth endoplasmic
reticulum has a variety
of functions:
1. Synthesizes lipids
2. Processes toxins and
drugs in liver cells
3. Stores and releases
calcium ions in muscle
cells
Rough endoplasmic reticulum makes membrane and
proteins
Ribosomes on the sur face of the rough ER produce proteins
that are secreted, inserted into membranes, or transported
in vesicles to other organelles
•Lysosomes are
sacs of enzymes
that function in
digestion within a
cell
•Lysosomes in
white blood cells
destroy bacteria
that have been
ingested
•Lysosomes also
recycle damaged
organelles
The various
organelles of the
endomembrane
system are
interconnected
structurally and
functionally
Moving the cells around
3 ways:
1. Flagellum—cell
extends cytoplasm
into tail-like
structure
2. Cilia—cell extends
small hair-like
structures
3. Pseudopodia—cell
extends itself to
move around
Human cells move too!
1. Lung cells & fallopian tube cells
use cilia to move things
around.
2. Male sperm cells use a
flagellum to get to the egg.
3. White blood cells use
pseudopodia to move between
other cells and get to where
they need to be.
Lecture Assignment 2
• Pages 485-511 in back of textbook
• Topic is cancer
• 1 page summary, handwritten, in your own
words, due Thursday, April 17, at the
beginning of class
Organelles
• Membrane surrounds them
• Important organelles:
•
•
•
•
•
•
•
Nucleus
Cell membrane
Lysosomes/peroxisomes
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Golgi apparatus
Special organelles involved in energy:
• Mitochondrion—produces ATP (in all eukaryotes)
• In plants and some algae: Chloroplast—produces
sugar from light energy
Mitochondria
Chloroplast
Can human diseases result from
organelles? Yes!
•Lysosomes
•Mitochondria
•Peroxisomes (in plants)
•Even Cell Membranes!
•Aging?
•Chronic Fatigue Syndrome?
Quick Review!
• What are 5 organelles in the cell?
• In order, what organelles are responsible for
moving the products of DNA to the Golgi
Complex?
• What 3 things make up the cell membrane?
• What are the 4 foundational theories of
biology?
• What are the 4 groups of biologicallyimportant molecules?