Biology EOC Class #3 Room 221 Mrs. Gleb

Class Three Plan! Cells Photosynthesis Writing: Conclusions Assessment – Cells Assessment – Photosynthesis Practice Test Questions (if there is time!)

Cells

Cell Theory All living things are composed of cells Cells are the basic unit of function and structure in living things All cells come from pre-existing cells

Eukaryotic vs. Prokaryotic Contains Nucleus Many organelles present 10-100 micrometers Appeared later in the fossil record (more recent) No Nucleus No Organelles 1-10 micrometers Appeared earlier in the fossil record

Prokaryote Eukaryote

Cell Structure Cell Organization- Eukaryotic cells can be divided into two major parts Nucleus Contains the cell DNA Cytoplasm (area outside the nucleus)

Function of Cell Organelles Vacuoles Sack-like structures that store materials like water, salts, proteins, and carbohydrates Vesicles Smaller structures that store and move materials between cell organelles and the cell surface

Function of Cell Organelles Lysosomes Small organelles filled with enzymes Break down lipids, carbohydrates, and proteins into small molecules Remove junk that would otherwise remain inside the cell “clean-up” crew

Organelle Function – Building Proteins Ribosomes Small particles of RNA Produce proteins Endoplasmic Reticulum Where lipids and proteins are assembled Golgi Apparatus Sorts and packages proteins for storage or release

Organelle Function Capture and Release Energy Chloroplasts Found in plants Capture energy from sunlight and convert to food Mitochondria Convert chemical energy stored in food into compounds that are more convenient for the cell to use

Cell Transport Passive Transport Movement of materials across the cell membrane without using cellular energy Diffusion Moving particles from areas of high concentration to areas of low concentration Facilitated Diffusion (Osmosis) Molecules pass through special protein channels – fast and specific

Osmosis – facilitated diffusion Water enters the cells through aquaporin Isotonic (cell stays the same size) Concentration of solutes is the same inside and outside the cell Hypertonic (cell shrinks) Higher concentration of solutes outside the cell Hypotonic (cell swells) Lower concentration of solutes outside the cell Osmotic Pressure

Active Transport The movement of materials against a concentration difference Molecular Transport Small molecules and ions are carried across membranes by proteins that act like pumps Bulk Transport – larger molecules and material are transported across membranes Endocytosis- taking material into the cell by in-folding the membrane (forming pockets) Exocytosis – releasing material to outside the cell

Homeostasis & Cells Homeostasis Multicellular Life Constant internal and external conditions Multicellular Life Cells become specialized for particular tasks Cell Specialization Levels of Organization Tissue – group of cells that perform a task Organ- many groups of tissue working together Organ System – a group of organs working together Cellular Communication Cells communicate through chemical signals and receptors

Photosynthesis Energy & Life

Chemical Energy & ATP ATP Storing Energy Releasing Energy Using energy Adenosine Triphosphate Fuel for cells Storing Energy ADP – a way for cells to store ATP Releasing Energy Energy is released by breaking bonds between ATP Using energy Cells keep large amounts of ADP on hand as a way to create ATP to use

Heterotrophs & Autotrophs Obtain food by consuming other living things Autotrophs Make their own food Photosynthesis Converting energy of sunlight into chemical energy stored in the bonds of carbohydrates

Photosynthesis Chlorophyll and Chloroplasts Light & Color Plants gather the sun’s energy with pigments The principal pigment is chlorophyll Chlorophyll absorbs light well in blue-violet & red spectrum and REFLECTS green This is why plants look green!

Chloroplasts Chloroplasts contain lots of saclike membranes called thylakoids. Thylakoids are arranged in stacks called granum Pigments are inside the granum The rest of the chloroplast is fluid called stroma

Photosynthesis

Light Dependent & Light Independent Reactions Reactions that directly involve light and light-absorbing pigments Water is required Oxygen is released as a byproduct Plants absorb carbon dioxide and complete photosynthesis by producing sugars No light is needed

Light Dependent Reactions Generate ATP and NADPH Use sunlight to convert ATP into ADP and NADP into NADPH ADP and NADPH are energy carriers Occur in the Thylakoids Use Pigments

Light Independent Reactions Plants use the ATP and NADPH to build stable compounds (sugars and carbs) for energy This is called the Calvin cycle

Factors that impact Photosynthesis Temperature Enzymes function best between 0 – 35 degrees Celsius Light High intensity light makes the plants photosynthesis faster Water Water is a reactant that is needed

Writing on the EOC You MUST write something on these sections! These questions are where the most students lose points – do not skip them Carefully review each writing question and underline the components that your answer should have

Types of Short Answer / Writing Questions Conclusions Answer the question Include supporting data from the IV & DV table Explain how the data support your conclusion Provide an explanation for the trend in the data