BLAST FROM THE PAST!
1. Define: Manipulated variable
Responding variable
2. Convert: 34,758,900m = _________km
1.6L = ______ ml
3. Given: MV = amount of artificial light
RV = plant growth
Write a possible formal hypothesis.
4. Describe: The difference between a
qualitative and a quantitative observation.
Include examples.
1. Define: MV – variable that is changed on purpose by
the scientists
RV – variable that changes b/c of the MV;
variable that is measured in the experiment.
2. Convert: KHD b/u dcm
34,758.9 km
1600mL
3. Hypothesis: If the amount of artificial light is related to
plant growth, then increasing the amount of light
will make the plant grow taller.
4. Describe: Qualitative Observation – Describing an object
based on one’s 5 senses. Ex. The potato feels soft
and bendy.
Quantitative Observation – Describing an
object based on some type of measurement. Ex.
The potato has a mass of 1.7 g.
CHEMICAL COMPOUNDS
IN CELLS
PAGES 74-78 IN TEXT BOOK
So What’s an ELEMENT?
• Any substance that cannot be broken
down into simpler substances.
Everything on this planet, living or nonliving, is made up of elements.
• About 100 different elements are found
on the Earth
• Each element has its own
characteristics and properties
– Ex – Sulfur in its pure form is a yellow,
solid, crystal.
• The smallest unit of an element is an
atom. Elements are only made up of
one kind of atom.
Before we can talk about “chemical compounds”
in cells, we have to find out what a compound IS.
• COMPOUND – two or
more elements that
combine.
• This is one molecule
of a compound called
ammonia NH3
– 1 atom of Nitrogen
– 3 atoms of Hydrogen
Chemical compound called ammonia or NH3.
This is a molecule of water
• 1 atom of Oxygen
• 2 atoms of Hydrogen
How many atoms of each element do
you see in this molecule of glucose?
Compounds
• Carbon dioxide
CO2
• Water
H2O
• Sugar
C6H12O6
• Salt
NaCl
• Hydrochloric acid
HCl
The Compound Called Water
•
•
•
•
Water makes up about 2/3 of our body.
All chemical reactions take place in water
Water gives the cell its size and shape
Water is also in the environment outside
the cell as well
Inorganic vs. Organic Compounds
• Organic compounds:
compounds that contain
carbon (except CO2)
– Example – glucose C6H12O6
• Inorganic compounds:
compounds that DO NOT
contain carbon
– Examples – water (H2O),
table salt (NaCl)
Important Organic Compounds
• The four main organic compounds found in
all living things are:
–
–
–
–
Carbohydrates
Lipids
Proteins
Nucleic Acids
• They all have one thing in common – they
have the carbon atoms in them
CARBOHYDRATES
• Job: Give the cell energy
• Simple carbohydrates are sugars (C, O, H)
– Lactose
– Sucrose
– Glucose
• Complex carbohydrates are starches.
– Cellulose – plant cell walls are made up of cellulose
– Starches stored in plants (potatoes, pasta, rice)
LIPIDS
• Job: Back up energy
reserve for the cell.
• Hydrophobic – cannot mix
with water due to their
structure
• Cell membranes are made
mainly of lipids
PROTEINS
• Job: Form parts of the cell
membrane and make up many of
the cell organelles
• Made up of smaller molecules
called amino acids
– There are 20 amino acids
– The structure and function of a
protein depends on how many and
in what order amino acids are
found in the molecule.
• Think of amino acids like letter
in the alphabet
A Special Type of Protein
• Enzymes: type of protein
that speeds up a chemical
reaction in a living thing.
– Acts like pouring gasoline on Cheese is made by inserting
a fire. (Speeds up the
enzymes into milk.
reaction of the fire.)
– Example: Enzymes in your
saliva break down starch
into sugars in your mouth,
speeding up the digestion
process.
Enzymes are put in some
detergents to help remove
tough stains. They speed
up the process of breaking
down stains on our clothes.
NUCLEIC ACIDS
• Job: Holds instructions
for everything that goes
on in a cell.
• Two kinds
– DNA – carries information
about an organism; passed
from parent to offspring
– RNA – plays a role in
making proteins
C, H, O , N, P