How Cells
Function
Chapter 2
2.1 What are cells made
of?
• All cells are made of the same elements.
• All matter in the universe living and nonliving are
made of particles called atoms.
• Different substances are made with different types
of atoms. Each element has its own type of atoms
and its own properties.
• Example- O- oxygen
2.1
• A molecule consists of 2 or more atoms.
• Most of the activities that take place in cells involve
the interaction of atoms and molecules.
• A chemical reaction is a process in which bonds
between atoms are broken and new bonds are
formed.
• Energy is needed to break the bonds between
atoms.
2.1 Large Molecules
• Large molecules support cell function.
• There are 4 main types of large molecules that
make up living things: carbohydrates, lipids,
proteins, and nucleic acids.
• These molecules work together in a cell.
• These large molecules are made up of smaller
parts called subunits.
2.1 Carbohydrates
• A carbohydrate is a type of molecule made up
of subunits of sugars.
• Carbohydrates are used for energy.
• Simple carbohydrates or sugar molecules can
be linked together in a long chain to form
more complex carbohydrates, such as starch,
cellulose, and glycogen.
• Plants make cellulose, which makes up the
cell wall.
2.1 Lipids
• Lipids are the fats, oils, and waxes found in
living things.
• Most lipids do not dissolve in water.
• Lipids can be used for energy and for making
structures.
• Lipids are used to help make cell membranes
that surround the cell and its organelles.
2.1 Proteins
• Proteins are a type of molecule make of smaller
molecules called amino acids.
• The structure and function of a protein are
determined by the type, number, and order of the
amino acids in it.
• We get proteins from foods such as meat, eggs,
cheese, and some beans.
• Proteins help support growth and repair of cells, help
our muscles to function, helps deliver oxygen, and
helps transport in/out of a cell
2.1 Nucleic Acids
• Nucleic acids are the molecules that hold the
instructions for cells to develop, grow, and
reproduce themselves.
• There are 2 types of nucleic acids: DNA and RNA.
• The subunit of nucleic acids are nucleotides.
• DNA provides the information used by a cell for
making proteins the cell needs.
2.1 Cells
• About 2/3’s of every cell is water.
• Most lipids do not dissolve in water.
• A cells membrane is made of a double layer of
lipids.
• This makes a barrier between the inside and
outside of the cell.
2.1 Question: ____are fats,
oils, and waxes found in
living things.
• A. Lipids
• B. Proteins
• C. Carbohydrates
• D. Nucleic Acids
• E. DNA
2.1 Question: ____are made
up of sugar and give us
energy.
• A. Lipids
• B. Proteins
• C. DNA
• D. Nucleic Acids
• E. Carbohydrates
2.1 Question: _____are
made of amino acids and
help our muscles to grow
and function.
• A. Lipids
• B. Proteins
• C. Carbohydrates
• D. Nucleic Acids
• E. Nucleotides
molecules that hold the
information for cells to
grow and develop.
Examples RNA and DNA
• A. Lipids
• B. Proteins
• C. Carbohydrates
• D. Nucleic Acids
• E. Amino Acids
2.2 Cells capture and
release energy
• To stay alive, cells need a constant supply of
energy.
• All cells use chemical energy.
• Chemical energy is the energy stored in the
bonds between atoms of every molecule.
• To stay alive, cells must be able to release the
energy stored in the bonds.
PHOTOSYNTHESIS
• Autotrophic Process: Plants and plant-like organisms
make their energy (glucose) from sunlight.
• Stored as carbohydrate in their bodies.
• 6CO2 + 6H2O + sunlight  C6H12O6 + 6O2
Why is Photosynthesis important?
Makes organic molecules (glucose) out
of inorganic materials (carbon dioxide
and water).
It begins all food chains/webs. Thus
all life is supported by this process.
It also makes oxygen gas!!
Photosynthesis-starts to ecological food webs!
Photo-synthesis
means "putting together with light."
Plants use sunlight to turn water
and carbon dioxide into glucose.
Glucose is a kind of sugar.
Plants use glucose as food for
energy and as a building block for
growing.
Autotrophs make glucose and
heterotrophs are consumers of it.
How do we know that plants make
carbohydrates from just carbon dioxide
water and lightExperiments!
energy?
• For example:
Jan Baptisa van Helmont (1648) planted a willow
branch weighing 5 pounds into 200 pounds of soil
and then after 4 years the tree weighed 169 lbs.
and the soil was still nearly 200 lbs.
Photosynthesis
sunlight
Carbon dioxide + water
glucose + oxygen
absorbed by chlorophyll
6CO2 + 6H2O + energy  C6H12O6 + 6O2
As can be seen from the equation for photosynthesis, the
wood, bark, and root came from water and carbon
dioxide.
Plants in
Action
Check it!
What is the
process
that
uses
the
sun’s
energy
to make
simple
sugars?
EQUATION FOR
PHOTOSYNTHESIS
WATER
6CO2 + 6H2O +ENERGY
CARBON
DIOXIDE
OXYGEN
C6H12O6 + 6O2
GLUCOSE
PHOTOSYNTHESIS
• 2 Phases
• Light-dependent reaction
• Light-independent reaction
• Light-dependent: converts light energy into chemical
energy; produces ATP molecules to be used to fuel
light-independent reaction
• Light-independent: uses ATP produced to make
simple sugars.
PHOTOSYNTHESIS
• What affects photosynthesis?
• Light intensity: as light increases, rate of photosynthesis
increases
PHOTOSYNTHESIS
• What affects photosynthesis?
• Carbon Dioxide: As CO2 increases, rate of
photosynthesis increases
PHOTOSYNTHESIS
• What affects photosynthesis?
• Temperature:
• Temperature Low = Rate of photosynthesis low
• Temperature Increases = Rate of photosynthesis increases
• If temperature too hot, rate drops
2.2 Cellular
Respiration
2.2
• Plants and animals can use energy and store
energy for later.
• In plants chloroplasts help capture sunlight to
make energy.
• In our cells mitochondria help to free the energy
for the work the cells do.
2.2 All Cells Release
Energy
• All cells can store energy and they can release the
energy that has been stored.
• Cellular respiration is the process in which cells use
oxygen to release energy stored in sugars such as
glucose.
• Photosynthesis occurs in organelles called
chloroplasts.
• Cellular respiration takes place in organelles
called mitochondria.
2.2 Cellular Respiration
• Starting Materials: Glucose and Oxygen
• Process: The mitochondria use oxygen to release
stored energy in glucose.
• Ending Products: Chemical energy, water, and
carbon dioxide
Glucose+Oxygen -> Chemical energy + water +
carbon dioxide
2.2 Fermentation
• Fermentation is the process by which cells
release energy without oxygen.
• There are two types of fermentation:
Alcoholic and Lactic Acid Fermentation
• Alcoholic releases alcohol and carbon dioxide
and lactic acid produces lactic acid
2.2 Uses of Fermentation
• Bread is made using fermentation.
• Bacteria and fermentation help make things like
yogurt, cheese, and sourdough bread.
• Exercise- your muscle cells are able to release
energy with Latic acid fermentation and cellular
respiration.
2.2 Exercise
• During hard exercise, your muscles may use up all
there stored energy and oxygen. Then your
muscles rely on fermentation to break down
sugars.
• The waste product from this is lactic acid.
• Your muscles become sore from a build up of lactic
acid
2.2 Question: ____is the
process where plant cells
change energy from the
sun into sugar.
• A. Cellular respiration
• B. Fermentation
• C. Oxygen
• D. Lactic Acid
• E. Photosynthesis
2.2 Question: ____ is the
process where
mitochondria use oxygen
to release stored energy.
• A. Cellular respiration
• B. Fermentation
• C. Photosynthesis
• D. Lactic Acid
• E. Chloroplasts
2.2 Question: _____ is the
process where cells release
energy without oxygen.
• A. Cellular respiration
• B. Fermentation
• C. Photosynthesis
• D. Lactic Acid
• E. Chloroplasts
2.2 Question: Which
organelle is used in
photosynthesis?
• A. Ribosomes
• B. Mitochondria
• C. Nucleus
• D. Chloroplasts
• E. Endoplasmic reticulum