1. Cell Processes and Energy
Chapter 2
Cell Processes and Energy

2. Section 4
Photosynthesis

3. Producers and Consumers
Autotroph = Producers
Heterotrophs = Consumers

4. Process of Photosynthesis
Process by which organism captures energy from the sun and uses it to make food
Stage 1: Capture sun’s energy
Green pigment called chlorophyll captures light energy from sun
Stage 2: Making food

5. Making food for plants Raw materials (needs) Products
Water – taken in by the roots
Carbon dioxide - enters the stomata (small opening on the underside of the leaves)
Products
Oxygen – most of it leaves the plant through the stomata
Sugar – glucose – C6H12O6 – food for plant

6. Photosynthesis Equation
Carbon
dioxide
Water
Glucose
Oxygen

7. Photosynthesis and Life
Nearly all living things either directly or indirectly receives energy from sun
EX: plant (autotroph- energy from sun)
Herbivores – eat plants and receive the sun’s energy from the plant
Carnivores – eat herbivores and receive the sun’s energy from their food

8. Respiration

9. Storing and releasing energy
When you eat, energy from the food is stored.
When you need energy, food is broken down to release energy.
Respiration: process of breaking down food to release energy
Cells need a continuous supply of energy so respiration is always occurring.

10. Respiration Equation Glucose Oxygen Carbon dioxide Water
Carbon dioxide and
Glucose comes from the food
water
diffuse out of cell
Oxygen comes from the air or water

11. 2 stages of respiration Stage 1 – cytoplasm Stage 2 – mitochondria
Glucose is broken down
No oxygen is needed
Only a small amount of energy is released
Stage 2 – mitochondria
Glucose further broken down
Oxygen is needed
Energy released

12. Photosynthesis and Respiration
Opposite processes
The 2 together form a cycle keeping oxygen and carbon dioxide in the atmosphere

13. Fermentation Provides energy for cells without oxygen
Less energy than respiration
1. Alcohol fermentation
Yeast – produces carbon dioxide (bread rises)
2. Lactic acid fermentation
Occurs when you exercise
Your cells need oxygen faster than you can take it in
Fermentation occurs to produce energy and a product is lactic acid. This causes your muscles to ache.

14. Cell division

15. Functions of cell division
Growth
Repair (broken bone, cut)
Reproduction (single celled organisms)

16. The Cell cycle Regular sequence of growth and division
A parent cell divides to form 2 identical daughter cells
3 main stages
Interphase
Mitosis
Cytokinesis

17. Stage 1: Interphase A. Growth B. DNA replication
Doubles in size
Copies all organelles
B. DNA replication
Copy DNA
C. Preparation for division
Produces structures necessary for division

18. Stage 2: Mitosis Cell’s nucleus divides into 2 nuclei 4 phases
Prophase: Nucleus condenses to form chromosomes
Metaphase: Chromosomes line up in the middle of the spindle
Anaphase: Chromatids move to end of cell
Telophase: new nuclear membrane forms

20. Stage 3: Cytokinesis Cytoplasm divides Organelles divide
Animal cell: cell membrane squeezes together to form 2 cells
Plant cell: Cell plate forms between the cells. This becomes a cell membrane. The cell wall forms outside it

21. Length of cell cycle Different for each cell Urchins 2 hours
Liver cells 22 hours
Brain cells Never
Prep
for Division
2 hours
Cell Division
1 hour
DNA
Replication
10 hours
Growth
9 hours