Cells Structure and Function Chapter 7

Lipid monomer = gylcerol and fatty acids Identify the class of lipids that form biological membranes (cell membrane)? Phospholipids Lipid monomer = gylcerol and fatty acids

Explain what it means to be a polar molecule

Distinguish between the terms hydrophilic and hydrophobic

Do you remember any of the eight characteristics of living things? Living things are based on a universal genetic code (DNA) Living things grow and develop Living things respond to their environment (stimulus) Living things reproduce Living things maintain a stable internal environment (homeostasis) Living things obtain and use material and energy (metabolism) Living things are made up of CELLS Taken as a group, living things evolve over time

Some short videos/songs for Cell Theory History and Scientists of Cell Theory Cell Theory Rap :)

Anton van Leeuwenhoek Developed the first microscope

Robert Hooke (1665) English physicist used a primitive compound microscope to look at plant tissue (stems, wood, and cork). Discovered cells He called the chambers “cells” because they reminded him of the small rooms in a monastery

Robert Brown Discovered the nucleus

Mathias Schleiden Stated that all plants are made of cells

Theodor Schwann Stated that all animals are made of cells

Rudolf Virchow (1855) Stated that all cells arise from the division of preexisting cells

The Cell Theory: All living things are composed of cells Cells are the basic unit of structure & function in living things All cells come from preexisting cells

Two Types of Cells:

Two Types of Cells: Prokaryotic Cell or Prokaryote – unicellular organism that lacks a nucleus pro = before; karyon = nucleus or kernel contain cell membranes and cytoplasm but no nucleus DNA is scattered through cytoplasm examples: bacteria

Two categories of cells Eukaryotic Cell or Eukaryote – organism whose cells contain a nucleus ( plant and animal) eu = true; karyon = nucleus or kernel contain a nucleus that holds DNA and membrane bound organelles that have specific functions examples: all plants, animals, some fungi, some microorganisms

Differences between prokaryotic and eukaryotic cells: Prokaryotes: Eukaryotes: No Nucleus (Nucleoid) No membrane-bound organelles “O” shaped chromosome (plasmid) Have a Nucleus Membrane-bound organelles “X” shaped chromosomes

Two categories of cells Prokaryotic Eukaryotic -Nucleus -Unicellular -No Nucleus -Complex -Cell wall (plants and bacteria) -Membrane bound organelles -Less complex -Smaller Ribosomes less complex -Cell membrane -Multicellular -DNA - Ribosomes larger and complex -Cytoplasm -DNA is circular -Ribosomes -DNA is X shaped -Living things 0.1-10µm 10-100µm

Animal Cell - Eukaryotic Prokaryotic Plant Cell - Eukaryotic Animal Cell - Eukaryotic

Prokaryotes and Eukaryotes:

Cell Organelles

How small are cells? How much is a micrometer? 1 micrometer (µm) = 1/1,000,000 m Typical cell size = 5 to 50 µm in diameter In a dice that is 1 cm3 We could fit 1,000,000 cells Cells Alive

How small are cells?

Cell Organelles: specialized structures that perform a specific function inside of a cell Cytoplasm Nucleus Nucleolus Nuclear Envelope Vacuole Lysosome Cytoskeleton Centrioles Ribosomes Endoplasmic Reticulum Golgi Apparatus Chloroplast Mitochondria Cell Wall Cell membrane Cilia & Flagella

Cytoplasm: Found: between the nucleus and the cell membrane Structure: a clear “jelly-like” material Function: supports the organelles

Nucleus: control center of the cell Found: in the cytoplasm near middle of cell Structure: filled with chromatin (tightly coiled DNA) Function: Stores hereditary information (DNA) Prokaryotic cells lack a nucleus, but they do contain DNA

Chromatin and Chromosomes: Inside the nucleus are fine strands of chromatin = a complex of DNA bound to protein Chromatin coil up and become densely packed, forming chromosomes Chromosomes are visible under a microscope when a cell divides

Nucleolus and Nuclear Envelope: Nucleolus – small dense region within the nucleus where ribosomes are synthesized Nuclear Envelope – double membrane (lipid bilayer) that surrounds the nucleus -allows materials to move out of the nucleus Nuclear Pore – allows RNA and proteins out of the nucleus

Vacuole: Found: in the cytoplasm Structure: sac-like, fluid-filled organelles Plant cells, there is a single large central vacuole filled with fluid - can occupy up to 90% of the cell’s volume Animal cells – much smaller Function: storage structure (water, salts, proteins, and carbohydrates) Animal Animal Plant

Paramecium’s Contractile Vacuole Contracts rhythmically to pump excess water out of the cell – controls the water content of the organism Paramecium Contractile Vacuole

Lysosomes: Found: In the cytoplasm Structure: Small enzyme filled organelles Function: Breakdown large organic molecules, and old nonfunctioning organelles Removes “junk” that would clutter the cell Known as the “Clean Up Crew” Found in animal cells and specialized plant cells Some humans have diseases that result from lysosomes that fail to function properly.

Cytoskeleton: Found: Throughout the cell Structure: A network of protein filaments Microtubules (25 nm) Microfilaments (7nm) Function: Gives cells structure; helps to maintain shape & size; involved in cell movement Helps to transport materials between different parts of the cell Network of protein strands (scaffold)

Microfilaments: Thin threads made of actin (structural protein) Supports the cell Contribute to cell movement

Microtubules: Larger strands; hollow tubes made of tubulin (proteins) Maintain cell shape Important in cell division – forms the mitotic spindle which helps to separate chromosomes Form centrioles in animal cells Help build cilia and flagella

Centrioles: Found: Within the cytoplasm only in animal cells Structure: Made of a microtubules (tubulin) arranged in 9 groups of 3 Function: Used to organize cell division (mitosis) 9 8 1 7 2 6 3 5 4

Centrioles - Mitosis

Cilia: Short hairs present in large numbers Propel unicellular organisms Line cells of respiratory tract

Flagella: Longer hairs that are less numerous Found on sperm cells Whip back and forth

Ribosomes: Found: Most numerous organelle – found throughout the cytoplasm in all cells Structure: Small and grain-like, made of large and small subunits; not surrounded by a membrane Function: Produce PROTEINS by following coded instructions that come from DNA Made of RNA and protein in the nucleolus & transported to the cytoplasm

Endoplasmic Reticulum (ER): Found: just outside the nucleus Structure: System of membranous tubules & sacs Function: Moves molecules from one part of the cell to another Intracellular Highway

Rough ER: Dotted with ribosomes Involved in the synthesis of proteins Abundant in cells that make large amounts of protein

Smooth ER: Does not have ribosomes attached Contains collections of enzymes that perform specialized tasks (i.e. detoxifying - liver)

Golgi Apparatus: Found: in the cytoplasm Structure: Processing, packaging, and secreting organelle Function: Modifies, sorts and packages proteins and other materials for storage or release Works with the ER Modifies proteins for export

Mitochondria: Found: in the cytoplasm Function: Convert chemical energy stored in food into compounds that the cell can use – “powerhouse” of the cell Transfer energy to ATP (main energy currency) Surrounded by two membranes and contain DNA Most numerous in cells with high energy requirements (liver & muscle) How Cells Obtain Energy

Chloroplast: Found: Only in the cytoplasm of plant cells Structure: Stack of membranes that contain photosynthetic pigments (chlorophyll) Function: Capture energy from the sun& convert it to chemical energy (food) - photosynthesis Surrounded by two membranes and contain DNA Contains the green pigment chlorophyll Plastid – major organelle found in plant and algae cells. Plastids are the site of manufacture and storage of important chemical compounds used by the cell. They often contain pigments used in photosynthesis, and the types of pigments present can change or determine the cell's color. Plastids can also store products like starch, fat, protein and can synthesize fatty acids.

Cell Wall: Found: Rigid structure outside the cell membrane Structure: Made of cellulose Function: Supports and protects the cell Found only in plant cells

Cell Membrane: Found: Located around the perimeter of the cell Structure: Made primarily of lipids and proteins Function: Regulates what leaves and enters the cell and provides protection and support Selectively permeable

Fluid Mosaic Model:

Components of Cell Membrane: Phospholipids – polar head & nonpolar tails Integral Proteins – imbedded in lipid bilayer; usually have carbohydrates attached to them Peripheral Proteins – surface only

Animal Cell:

Plant Cell:

Animal Cell - Label Centriole Cell membrane Cytoplasm Lysosome Rough ER Nucleus Nucleolus Smooth ER Nuclear envelope Ribosomes Vacuole Golgi Apparatus Mitochondria

Plant Cell - Label Cytoplasm Cell wall Plastid Cell membrane Vacuole Nucleus Rough ER Nucleolus Smooth ER Nuclear envelope Ribosomes Chloroplast Golgi Apparatus Mitochondria

Plant and Animal Cell Comparison

Classification – Prokaryotes/Eukaryotes Prokaryotes (Kingdom Monera): 1. Archaea (love extreme cold or heat – food is diverse) 2. Bacteria – regular prokaryotes Eukaryotes: Everything else (plant, animal, fungi, ciliates, etc.)

Great websites to check out! Interactive Cell Models – Cells Alive http://www.cellsalive.com/index.htm Inside a Cell – Learn.Genetics (University of Utah) http://learn.genetics.utah.edu/content/begin/cells/insideacell/ Video – BBC Secret Universe: The Hidden Life of the Cell http://www.youtube.com/watch?v=4GZXRMG5i_w Video – Inside the Cell http://www.youtube.com/watch?v=Ao9cVhwPg84