1. Cell Processes and Energy
Unit 6:
Cell Processes and Energy

2. Chemical Compounds in Cells
Element- any substance that can’t be broken down into simpler substances.
- Ex: oxygen and nitrogen
Compound- When two or more elements combine chemically, they form a compound.
- Ex: water and carbon dioxide

3. Chemical Compounds in Cells
Water-
a) Made up of 2 hydrogen and 1 oxygen atoms
b) Dissolves chemicals that cells need
c) Most chemical reactions in cells could not take place withOUT water.
d) Helps cells keep their size and shape.
e) Helps maintain a stable temperature (water temp changes slower than air temp)

4. Chemical Compounds in Cells
Organic compounds- contain carbon
Inorganic compounds- do not contain carbon
- Ex: water and salt

5. Carbohydrates a) Organic compounds
b) energy-rich compound made of carbon, hydrogen, and oxygen
c) Ex: starch and sugar, fruit, bread
d) Sugar + sugar = starch
e) Plant cells use starch to store energy, used for short-term storage
f) Important components of cell parts Ex: Cellulose in cell wall

6. Carbohydrates

7. Lipids a) Ex: fats, oils, waxes
b) energy-rich compounds, made of carbon, hydrogen, and oxygen
c) Contain more energy than carbs
d) Cells store energy, used for long-term storage
e) Cell membranes are made of lipids

9. Proteins
a) Long organic molecules of carbon, hydrogen, oxygen, nitrogen and sometimes sulfur.
b) Ex: spider webs, fingernails, feathers, meat, eggs, nuts
c) Make up cell organelles
d) Proteins called enzymes help chemical reactions occur
e) Made of smaller molecules called amino acids
f) The order of amino acid linkage determines the protein’s identity

11. Nucleic Acids
a) Long organic molecules of carbon, hydrogen, oxygen, nitrogen, and phosphorus
b) Contain cells’ instructions for life
c) DNA (Deoxyribonucleic acid)– carries genetic info., passed from parent to offspring
d) RNA (ribonucleic acid)- important for protein synthesis

13. Molecule Movement
The cell membrane is semi-permeable which means some things can pass through it and others cannot

14. Molecule Movement
Diffusion- the main way small molecules move across the cell membrane.
a) Movement of molecules from high to low concentration
b) Cause of diffusion- Molecules bump into each other
c) Diffusion of oxygen- more oxygen outside cells than in, so oxygen moves from high to low concentration and enters cells.

16. Molecule Movement
Osmosis- The diffusion of water from an area of high concentration to an area of low concentration.
Many cellular processes depend on osmosis

17. Molecule Movement Molecule Movement
Osmosis- The movement of water to an area of higher dissolved materials .
Many cellular processes depend on osmosis

19. Cell Transport
a) Passive transport- movement of dissolved materials through a cell membrane without using the cell’s energy.
Ex: Diffusion and osmosis
b) Active transport- movement of dissolved materials through a cell membrane using the cell’s energy.
Ex: engulfing
c) Engulfing- cell wraps around a particle and engulfs it. Also called endocytosis.

21. Cell Transport d) Why are cells so small?
- Smaller cells= more surface area for movement of molecules. Less distance for cytoplasm to span.
e) Cells are small so they can be efficient!

22. Cellular Energy Every living thing needs energy
The sun is the source of energy for most living things
Photosynthesis
a) Photo- light
b) synthesis- to put together
c) Nearly all living things obtain energy either directly or indirectly from the energy of sunlight captured during photosynthesis
d) Autotroph- makes its own food
e) Heterotroph- obtain food by eating other organisms

23. Sources of Energy
Nearly all living things obtain energy either directly or indirectly from the energy of sunlight captured during photosynthesis.

24. Photosynthesis- Stage 1
Photosynthesis: Stage 1- Capturing the energy in sunlight
a) Happens in chloroplasts in leaves
b) Pigments- colored chemical compounds that absorb light. Gives leaves their green color
c) Cholorphyll- the main pigment in chloroplasts
d) See figure on pages 88-89

25. Photosynthesis- Stage 2
Photosynthesis: Stage 2- Using energy to make food
a) Cells need water (absorbed by roots from soil)
b) Cells need carbon dioxide (enters leaves from air)
c) Stomata- opening in leaves, allows carbon dioxide and oxygen to move in to and out of leaves
d) Happens inside chloroplasts, water and CO2 undergo chemical reactions

26. Photosynthesis- Stage 2
Photosynthesis: Stage 2- Using energy to make food
e) Reactions are powered by energy from the first stage
f) Plants produce sugar with the formula C6H12O6
g) Oxygen is produced and exits through stomata
sunlight
6CO2 + 6H2O  C6H12O6 + 6O2
Carbon Dioxide + Water  Sugar + Oxygen

27. The Two Stages of Photosynthesis
During photosynthesis, plants and some other organisms use energy from the sun to convert carbon dioxide and water into oxygen and sugars.

29. Cellular Respiration
Cellular Respiration- animal cells break down sugar and obtain energy
a) Your cells store energy until you need it
Respiration: Stage 1
a) Happens in cytoplasm
b) sugar is broken up into smaller molecules
c) oxygen is not involved (Anaerobic)
d) Releases a small amount of energy

30. Cellular Respiration Respiration: Stage 2 a) Happens in mitochondria
b) Small molecules from step one are broken down even further
c) Requires oxygen (aerobic)
d) Releases LOTS of energy
e) See page 92
C6H12O6 + 6O2  6CO2 + 6H2O
Sugar + Oxygen  Carbon Dioxide + Water

31. Two Stages of Respiration
During respiration, cells break down simple food molecules such as sugar and release the energy they contain.

32. Photosynthesis and Respiration
You can think of photosynthesis and respiration as opposite processes.

33. Fermentation Energy-releasing process that DOES NOT require oxygen
b) Energy released is much less than that during cell. resp.
c) Happens in environments that lack oxygen

34. Alcoholic Fermentation
d) Alcoholic Fermentation
- Happens in yeast and single-celled organisms
- Releases alcohol
- Also releases carbon dioxide and energy
- Used to make bread and beer

36. Lactic Acid Fermentation
e) Lactic Acid Fermentation
- Happens in your muscles
- Produces lactic acid
- Makes your muscles
sore
- Happens when muscle
cells use up oxygen faster
than it can be replaced