Organization of Living Organisms CELLS Organization of Living Organisms

Do Now Copy these questions & answer them while we watch the brain pop. 1. Name the organelles that they mentioned in the video and a brief function 2. The kidneys and intestines are compared to what 2 organelles in the cell? 3. Why do we have different types of cells?

Cell Theory All living things are made up of cells Cells are the basic unit of structure and function for all living things All cells arise from pre-existing cells

Cells specialize and are grouped into tissues Different tissues combine to form organs Several organs form systems to carry out life functions

Cells = The basic structure of life! Cells have specific structures that perform specific jobs called ORGANELLES Organelles are floating in the jellylike substances in the cell called CYTOPLASM

Cellular Organization Every human cell has: Plasma Membrane (cell membrane) Surrounds cell and keeps it intact Regulates what goes in and out of the cell Phospholipid bilayer that is semipermeable (allows only certain molecules in) Nucleus Large, centrally located Contains chromosomes Control center of the cell Controls metabolic functioning & structural characteristic of cell Cytoplasm Found between the nucleus and plasma membrane Contains water and various types of molecules Contains organelles

Cellular Organization Organelles Small, membranous structures Each has a specific function Keeps various cellular activities separate from each other Cytoskeleton Network of interconnected filaments and microtubules in cytoplasm Maintains cell shape and all the cell and contents to move

Plasma Membrane Thin structure that surround the cell – composed of lipids and proteins Important functions: Separates contents of cell from outside environment Controls which molecules enter and leave the cell (selective barrier) Recognize and respond to chemical signals with “receptor” molecules  allow interactions between cells

Phospholipid Bilayer Has attached/embedded proteins Polar head and nonpolar tails Polar heads are charged, hydrophilic, face outward Nonpolar tails are hydrophobic, face inward At body temperature the bilayer is a liquid, consistency of olive oil. Fluid-mosaic model –description of membrane structure Protein molecules have changing pattern Short chains of sugar are attached to outer surfaces of some proteins & lipids Glycoproteins, glycolipids Glycoproteins are specific to each cell and belong to specific individuals

Do Now Take out homework from Tuesday Night What are the 3 main parts of the human cell? What is the fluid-mosaic model?

Nucleus Stores genetic information Control center of the cell Every cell has genetic information, but each cell type has certain genes turned on and off Control center of the cell Metabolism is controlled here Contains a nucleolus Ribosomal RNA is produced here Surrounded by a nuclear envelope Has nuclear pores to allow certain proteins to pass through

Ribosomes Composed of two subunits, 1 large, 1 small Found free within the cytoplasm or attached to the endoplasmic reticulum Makes proteins

Endoplasmic Reticulum System of channels through the cell – communication and transport Smooth ER: no ribosomes Synthesizes phospholipids In testes – produces testosterone In liver – detoxifies drugs Rough ER: has ribosomes Proteins are made here then processed and modified Lysosome Contain digestive enzymes “suicide sacs” Join with vacuoles to break down food – If the lysosome ruptures or breaks the cell will die

Golgi Body Consists of a stack of 3 to 20 slightly curved saccules One side is directed toward the ER, other side is directed toward plasma membrane Packages secretions and transports materials, which are then carried in vesicles through the cytoplasm to other parts of the cell, or are excreted from the cell

Vacuoles & Peroxisomes Isolate substances captured inside the cell May contain parasites that are awaiting digestion by lysosomes Peroxisomes Similar in structure to lysosomes Vesicles that contain enzymes Detoxify drugs, alcohol and other potential toxins Found in great numbers in the liver and kidneys Break down fatty acids so that the fats can be metabolized

Mitochondria Bounded by a double membrane Site of ATP production Inner membrane folded to form shelves (cristae) Matrix (inner space) filled with gel-like fluid Site of ATP production Powerhouse of the cell

Centrioles Short cylinders with 9 outer microtubule triplets and no center microtubules Pair of centrioles is each cell Duplicate and separate during cell division

Cilia and Flagellum Projections from the cell. They are made up of microtubules. They are motile and designed either to move the cell itself or to move substances over or around the cell

Crossing the Plasma Membrane Lesson 2 Crossing the Plasma Membrane

Simple Diffusion Random movement of simple atoms or molecules from an area of high concentration to an area of low concentration until equal distribution NO ENERGY IS INVOLVED!!!

Osmosis Diffusion of water across the plasma membrane Occurs when there is an unequal concentration of water Osmotic pressure – force exerted on semipermeable membrane because water has moved from high concentration to lower concentration

Osmosis Solutes – dissolved substances Solution – water is more concentrated (least amount of dissolved substances, closest to pure water) Tonicity – degree to which a solutions concentration of solute vs. water causes water to move in or out of cells Isotonic – an equal concentration of solutes and solvent on both sides of membrane Hypotonic – solutions that cause cells to swell Hypertonic – solutions that cause cells to shrink

Filtration Movement of liquid from high pressure to low pressure Occurs in capillaries, pushes water and dissolved solutes out of the capillary through tiny pores

Transport by Carriers Facilitated diffusion – a molecule is transported across the plasma membrane from high concentration to low concentration by means of a helper protein. NO ENERGY REQUIRED Active transport – molecule is moving from low concentration to high concentration. ENERGY REQUIRED!!!

Endocystosis vs. Exocytosis Endocytosis Exocytosis Portion of plasma membrane forms an inner pocket to engulf a substance Membrane pinches off to form a vesicle Two forms Phagocytosis – cell eating Pinocytosis – cell drinking Vesicle fuses with plasma membrane as secretion occurs

Content Check Which process requires cellular ATP energy? A. osmosis B. facilitated diffusion C. active transport D. simple diffusion Video

Homework Study Questions #7-12

Lesson 3 The Cell Cycle

Do Now Take out Homework From last night Take out Cell Division video worksheet Cell Division

Cell Cycle Orderly set of stages that take place between the time a cell divides and the time the daughter cells divide Apoptosis – programmed cell death Stages: Interphase – not dividing, carries on regular activites, gets ready to divide G1 Phase – return to normal pre-mitotic condition S phase – DNA replication occurs G2 phase – cell synthesizes proteins that will aid in cell division

DNA Replication An exact copy of DNA is produced Each strand of the helix is used as a template Before replication - two strands are hydrogen bonded to one another During replication – old strands “unzip” and unwind New strands are made, enzyme DNA polymerase joins the new nucleotides together forming new helices. End result – two resulting double helices are identical. Each strand of double helix is equal to 1 chromatid, at the end of replication each chromosome is composed of 2 sister chromatids

Stages of Mitosis Prophase Metaphase Anaphase Telophase

Prophase Two pairs of centiroles are moving to opposite ends of the nucleus Spindle fibers appear Nuclear envelope starts to disappear Chromosomes are visible Spindle fibers attach to centromeres

Metaphase Nuclear envelope is completely gone Paired chromosomes are at the equator Fully formed spindles

Do Now Take out Homework From Last night List the 5 stages of mitosis.

Anaphase Sister chromatids separate Each cell receives a copy of each type of chromosome Chromosomes begin to move to opposite ends of the cell

Teleophase and Cytokinesis Chromosomes arrive at the poles Chromosomes become indistinct again Cytoplasm begins to divide Cleavage furrow begins to occur – pinches the cell in half Mitosis

Homework Study Questions pg 62 #13, 14, 16 & 17

Protein Synthesis DNA is template for RNA formation and protein construction Two Steps: Transcription – mRNA (messenger RNA) is produced Translation – mRNA specifies the order of amino acids in a polypeptide

Transcription DNA unzips and unwinds, binding with their RNA counterparts Joined by RNA polymerase -> RNA molecule results Three forms of RNA Messenger Transfer Ribosomal Codon – a sequence of three bases that is complimentary to the DNA triplet(ex. AAG)

Translation Uses several enzymes and all 3 types of RNA Transfer RNA (tRNA) deliver amino acids to ribosomes which are composed of rRNA (ribosomal RNA) and protein At least 1 tRNA molecule for each of the 20 amino acids Anticodon – a group of 3 bases that is complimentary to an mRNA codon

Animation

In class assignment/Homework Read Focus on Forensics “DNA Fingerprinting” Why is DNA so important to us? How is DNA extracted from a sample? Study Question 15, on page 18-19