Chapter 2 Cell Structure and Function

1. Chapter 2Cell Structure and Function

2. Cells and Life • Understanding Cells • Microscopes are used to view cells • Robert Hooke • looked at cork under the microscope • Cells – cellula-Latin for “small rooms” • The Cell Theory • Scheiden and Schwann were 2 scientists that pointed out plant and animal cells have similar features. • Virchow stated that all cells come from preexisting cells • Cell Theory • Living things are made of one or more cells • Cell is the smallest unit of life • All new cells come from preexisting cells

3. Basic Cell Substances • Macromolecules – many small molecules joined together that are found in cells. • Water • More than 70% of a cell’s volume • Essential for life • Surrounds the cell • Maintains a cell’s homeostasis • It’s structure (positive ends and negative ends) allow it to dissolve many substances.

4. Macromolecules • Large molecules that form when smaller molecules join together • 4 types of macromolecules • Nucleic acids • Proteins • Lipids • Carbohydrates

5. Nucleic Acids • Nucleic Acids – macromolecules that form when long chains of molecules called nucleotides join together. - DNA (deoxyribonucleic acid) - contain genetic information - passed from parents to offspring - instructions for cell growth, cell reproduction, and cell processes - used to make RNA - RNA (ribonucleic acid) - reads and interprets DNA - brings DNA’s information out of the nucleus - used to make proteins

6. Proteins • Proteins – long chains of amino acid molecules • RNA contains information for joining amino acids together • Different proteins have specific jobs • Ex. Amylase – found in saliva and beaks down food • Ex. Keratin – found in hair, horns, feathers and used for support

7. Lipids • Lipids – large macromolecules that do not dissolve in water. - used as a protective barrier in cells - major part of cell membrane (phospholipids) - energy storage (cholesterol) - cell communication

8. Carbohydrates • Carbohydrates – made of one, two, or a long chain of sugar molecules. - store energy (sugars & starches) - structural support (cellulose) - communication between cells

9. Lesson 1 Review Pg. 48 #’s 1-10

10. The Cell • Cell Shape and Movement • Size & Shape relate to job & function • Ex. – blood cells (carry oxygen and travel through vessels) - nerve cells (projections send signals) - plant cells (hollow/tube-like to carry water)

11. Cell Membrane • Cell membrane – a flexible covering that protects the inside of a cell from the environment outside - made of proteins and a phospholipid bi-layer

12. Cell Wall • Cell wall – a stiff structure outside the cell membrane. - found in plant, fungal, bacteria, and some protists. - protection, cell shape, and support

13. Cell Appendages • Flagella – long tail-like appendages that are used for movement. • Cilia – short hair-like structures that can move a cell or move molecules away from a cell.

14. Cytoplasm and Cytoskeleton • Cytoplasm – a fluid inside a cell that contains salts and other molecules - interior of the cell • Cytoskeleton – is a network of threadlike proteins that are joined together. - forms a framework for shape and movement

15. Cell Types • Prokaryotic Cells (prokaryotes) • No membrane around genetic material • Lack other cell parts • Eukaryotic Cells (eukaryotes) • Genetic material surrounded by a membrane • Organelles – structures with specialized functions • Larger than prokaryotic cells • Plants, animals, fungi and protists

16. Cell Organelles • Organelles enable cells to carry out different functions at the same time • Nucleus – directs cell activities and contains DNA (genetic information on chromosomes) - largest organelle - contains proteins - has a nucleolus – makes ribosomes (organelles involved in the production of proteins) - surrounded by a nuclear envelope which contain pores for RNA and ribosomes to move in out of.

17. Manufacturing Molecules • Rough Endoplasmic Reticulum (ER) – web like organelle attached to the nucleus with ribosomes on it where protein production begins. • Smooth Endoplasmic Reticulum (ER) – makes lipids and removes harmful substances from the cell.

18. Processing Energy • Mitochondria – organelles that process energy for the cell. - surrounded by 2 membranes - Adenosine Tri-Phosphate (ATP) is a molecule involved in chemical reactions where energy is released for cell growth, division, and material transport. • Chloroplasts – membrane bound organelles that take sugar and convert it to energy in the process of photosynthesis. - found in plants, protists, and algae

19. Processing, Transporting, and Storing Molecules • Golgi Apparatus – prepares proteins for their specific job and function. - packages the proteins into vessicles. • Vessicles - organelles that transport substances from one area of a cell to another. - Lysosomes – found in animal cells used to break down and recycle cellular components • Vacuoles – organelles that store food, water, and waste materials. - plants have large vacuoles for storing water

20. Lesson Review Pg. 58 #’s 1-11

21. Moving Cellular Materials • Cell membrane – only allows certain materials in and out (semipermeable) • Passive Transport – movement without energy - Oxygen and Carbon Dioxide • Types of Passive Transport • Diffusion – movement of substances from an area of high concentration to an area of low concentration until equilibrium is reached. • Osmosis – diffusion of water through a membrane. • Facilitated Diffusion – molecules that pass through a cell membrane using transport proteins

22. Active Transport – energy needed for movement - movement from low concentration to high concentration. - cells take in nutrients by way of carrier proteins. - wastes exit the cell by active transport. • Types of Active Transport • Endocytosis – cells take in substances by surrounding it with a cell membrane • Exocytosis – a cell’s vesicle release contents outside the cell.

23. Cell Size and Transport • Area of a cell membrane (surface area) must be large compared to the volume of the cell for efficient cellular transport. Math Skills pg. 65

24. Lesson Review pg. 66 #’s 1 - 11

25. Cells and Energy • Cellular Respiration – series of chemical reactions that convert chemical energy in food molecules into a useable form of energy called ATP. (humans and animals) • Cellular Respiration Occurs in 2 parts of the cell. • Cytoplasm – glycolysis occurs here. - glycolysis – glucose(sugar) is broken down into smaller molecules. - small amounts of ATP • Mitochondria – requires oxygen. - the smaller molecules from glycolysis are broken down. - large amounts of ATP - waste products – water and CO2

26. Fermentation • Fermentation – reaction that eukaryotic and prokaryotic cells can use to obtain energy from food when oxygen levels are low. - less ATP produced than cell. resp. - occurs in cell’s cytoplasm. • Types of fermentation • Lactic acid - Glucose ATP + Lactic Acid - ex. (bacteria, fungi, = cheese, sour cream, yogurt) (humans = exercise) • Alcohol – Glucose ATP + CO2 + Alcohol - ex. (bacteria, yeast, = ethanol and CO2 make bread dough rise)

27. Photosynthesis • Photosynthesis – a series of chemical reactions that convert light energy, water, and CO2 into the food-energy molecule glucose and give off oxygen. (plants & unicellular organisms) • Requires Light Energy - chlorophyll – pigment that absorbs light - reflects green - chloroplasts – organelles that contain chlorophyll. - where the chemical reactions take place.

28. Cellular Respiration and Photosynthesis • The products of photosynthesis feed into the reactants of cellular respirations. • The products of cellular respirations feed into the reactants of photosynthesis. Cellular Respiration C6H12O6 +6O26CO2 + 6H2O + ATP (glucose) (energy) Photosynthesis 6CO2 + 6H2OC6H12O6 + 6O2 (glucose) light

29. Lesson 4 Review pg. 72 #’s 1 - 11