Bell Work: 1/14/14 1. Please pick up your Binder, pick up today’s notes, find your assigned seat and log-in to LEARN on your Laptop. 2. Please open the Cell Functions topic and open the Plants Cells vs. Animals & Transports Power Point and review to complete you notes.

17.0 Analyze the Relationships Within Living Systems 17.1 Explain the role of the cell and cellular processes.

Which of the following cells is a Prokaryote and a Eukaryote? A. B.

What is a cell? ■ The smallest unit that can carry all the processes of life

What is the cell theory? ■ The basic unit of structure and function within an organism is the cell ■ All living organisms are composed or one or more cells ■ Cells come only from existing cells ■ That cells are the smallest life forms capable of self-replication.

Why are cells important to Agriculture? ■ Without the ability to study cells, most of the advances in agriculture would not have taken place ■ Life processes take place on a cellular level ■ Everything in the production process of plants and animals must be understood at cellular level to make improvements

Cell Types ■ What kinds of cells exist in nature? ■ There are only two main categories of cells that comprise all life forms, no matter how complicated a life form may appear: ■ 1. Prokaryotes, and ■ 2. Eukaryotes.

Prokaryote Cells Prokaryotes are cells without a nucleus. They have genetic materials but are not enclosed within a membrane. Instead, the genetic material (DNA) of prokaryotes floats free in the cell.

Prokaryote Cells These include bacteria and cyanophytes. The genetic material is a single circular DNA and is contained in the cytoplasm, since there is no nucleus.

Eukaryote Cell These are cells with a nucleus. The genetic material is surrounded by a membrane much like the cells membrane.

Eukaryote Cell Eukaryotic cells are found in humans and other multi-cellular organisms (plants and animals) also algae, protozoa. They have both a cellular membrane and a nuclear membrane

What is an organelle? ■ A cell component that performs specific functions ■ Example – nucleus, cell membrane

Cell Membrane ■ The outer boundary of the cell ■ Gives shape and flexibility to the cell ■ Is semi-permeable

Cell Wall ■ Only in plant cells ■ Thicker then the membrane ■ Relatively inflexible ■ Protects and supports the cell

Cytoplasm ■ Semi-fluid material inside a cell ■ Helps to keep all organelles in place

Nucleus ■ The cells brain ■ Contains chromosomes ■ Involved in protein synthesis

Endoplasmic Reticulum (ER)‏ ■ Folded membrane ■ Transports proteins and other materials

Ribosomes ■ The site of protein synthesis ■ Can be attached to the ER or float loose in the cell

Golgi Body ■ Closely stacked flattened membranes ■ It is the processing, packaging and secreting organelle

Mitochondria ■ Breaks down food molecules and releases energy

Lysosome ■ Contains digestive enzymes ■ Digests and rids the cell of waste ■ Prevents bacteria and viruses from invading

Vacuole ■ Sack of fluid surrounded by a membrane ■ Stores food, enzymes or waste. ■ Animals cells have many small ones ■ Plant cells have one large on

Plant cell vs. Animal cell ■ Plant Cells have: ■ Cell Wall ■ One Large vacuole ■ Plastids (stores food or pigment which give color to plant)‏

Animal CellPlant Cell cell Plant cell vs. Animal cell

Cell Functions ■ Homeostasis and Transport Homeostasis The stable internal condition of a living thing Transportation across a membrane is essential for maintaining homeostasis Cell membranes help control homeostasis by controlling what substances pass in or out.

2829 Two Types of Transport Passive Transport Active Transport Passive Transport Diffusion Osmosis Facilitated Diffusion Ion Channels

30 31 simplest type of passive transport ■ The movement of molecules from an area of high concentration to an area of low concentration ■ Does not require the cell to expend energy Diffusion

32 33 Diffusion Principles ■ There is a concentration gradient-the difference in concentration of molecules across a space ■ Diffusion always occurs DOWN the concentration gradient from an area of HIGH concentration to an area of LOW concentration. ■ Diffusion driven by the kinetic energy the molecules possess-moves randomly

34 35 Diffusion Principles ■ Rate of diffusion depends on the temperature, size, and type of molecule that is diffusing ■ Molecules diffuse faster at higher temperatures ■ Small molecules diffuse faster than larger molecules

36 37 Diffusion Principles ■ Diffusion will eventually cause the concentration of the molecules to be the same throughout the space, and the concentration gradient will no longer exist ■ When this occurs the system is said to be in a state of equilibrium

38 39 Osmosis Passive Transport diffusion of water across a semi- permeable membrane from an area of high concentration to an area of low concentration.

40 41 Osmosis ■ Terms: ✹ Solute: substance being dissolved in solution ✹ Solvent: the substance in which a solute is being dissolved ✹ Solution: a mixture in which one or more substances are uniformly dissolved in another substance Ex: sugar + water mix Solute = ? Solvent = ? Solution = ?

42 43 Net Direction of Osmosis When the concentration of solute molecules is higher outside the cell, the solution is hypertonic to the cytosol. Water will move out of the cell

44 45 Net Direction of Osmosis When the concentration of solute molecules is lower outside the cell, the solution is hypotonic to the cytosol. Water will diffuse into the cell When a cell bursts it is called cytolysis

46 47 Net Direction of Osmosis When concentration of solute molecules outside the cell is equal to that inside the cell, the solution is isotonic to the cytosol. No net movement of water, water diffuses in/out at equal rates

4849 Net Direction of Osmosis Red Blood Cell