Post on 18-Jan-2016
CELLSChapter 7
CELL THEORY All living things are made of cells Cells are the basic units of structure
and function in living things New cells are produced from existing
cells
MICROSCOPES
Compound light microscope – allows light to pass through a specimen and uses two lenses to form an imageMagnifies to 1000xStains or dyes are used to show specific
featuresFluorescent dies are used to tag molecules produced by cells
MICROSCOPES
Electron microscopes – use beams of electrons that are focused by magnetic fields – can be used to see objects one billionth of a meterTransmission electron microscopes – thin slices , electrons pass through the specimen - 2D image
Scanning electron microscopes – a pencil-like beam is scanned over the surface – makes a 3D image
SEM images
PROKARYOTES AND EUKARYOTES All cells have a cell membrane - a thin
flexible barrier surrounding the cell Not all cells have a nucleus – a large
membrane-enclosed structure that contains genetic material in the form of DNA and controls many of the cells activities Prokaryotes - do not have a nucleus
Typically smaller and more simple Eukaryotes = have a nucleus
Typically larger and more complex Can be unicellular or multicellular
7.2 CELL STRUCTURE – EUKARYOTIC CELLS
The cytoplasm is the fluid portion of the cell outside the nucleus.
Many cellular structures act as if they are specialized organs. These structures are known as organelles, literally “little organs.”
THE CELL AS A FACTORYThe eukaryotic cell is much like a living version
of a modern factory. The specialized machines and assembly lines of
the factory can be compared to the different organelles of the cell.
Cells, like factories, follow instructions and produce products.
THE NUCLEUS
The nucleus = the control center of the cell It contains most of the cell’s DNA, the
instructions for making proteins and other important molecules
Nuclear envelope = surrounds the nucleus contains pores (holes) that allow material to go in and out of the nucleus
Chromosomes – carry the cell’s genetic information (DNA)
Found in the nucleus Nucleolus – a small dense region in the nucleus
Ribosomes are assembled here
ORGANELLES THAT STORE, CLEAN UP, AND SUPPORT
Vacuoles –large saclike structures with membranes Store water, salt, proteins, and carbohydrates In plants there is often 1 vacuole filled with liquid Also found in unicellular organisms and animals for storing
and moving materials
ORGANELLES THAT STORE, CLEAN UP, AND SUPPORT
Lysosomes – small organelles filled with enzymes Break down lipids (fats) , carbohydrates,
and proteinsHelp break down “old” organelles -
removes “junk” from the cellFound in animal cells and some plant cells
ORGANELLES THAT STORE, CLEAN UP, AND SUPPORTCytoskeleton – a network of protein
filaments that give cells shape and internal organizationHelps maintain cell shape and involved in
movementMicrofilaments – form a framework that
supports the cell and help them moveMicrotubules – hollow structures made of
proteins called tubulins and are involved in maintaining cell shape and in cell division Also form cilia and flagella Centrioles – located near the nucleus and organize cell
division in animals (made of tubulins)
ORGANELLES THAT BUILD PROTEIN
Ribosomes – the “protein factory” - where proteins are assembledsmall particles of RNA and protein found
throughout the cytoplasm in all cells. produce proteins by following coded instructions
that come from DNA. Each ribosome is like a small machine in a factory,
turning out proteins on orders that come from its DNA “boss.”
ORGANELLES THAT BUILD PROTEIN
Endoplasmic reticulum (ER) – an internal membrane system where lipids are assembled and proteins and other materials are exported from the cell. Rough endoplasmic reticulum (rough ER) – the ER
where protein synthesis occurs ribosomes on its surface Proteins made in the rough ER can be exported out of the cell or
transported to other locations in the cell Smooth endoplasmic reticulum (smooth ER) – the ER
where no ribosomes are found Contains enzymes to do tasks like making membrane lipids or
detoxification of drugs
ORGANELLES THAT BUILD PROTEIN
Golgi Apparatus - modifies, sorts and packages proteins and other materials from the ER for storage in the cell or transport out of the cell. Looks like a stack of flattened membranes “Ships” proteins to their final destination
ORGANELLES THAT CAPTURE AND RELEASE ENERGY
Chloroplasts – capture the energy from sunlight and convert it into food (photosynthesis) Found in plants and some other organisms “solar power plants”
ORGANELLES THAT CAPTURE AND RELEASE ENERGY
Mitochondria – “The POWER HOUSE” convert the chemical energy stored in food into
compounds easier for the cell to use In humans, you inherit most of your mitochondria
from your mom Contain small DNA molecules which suggest they may
have been descended from independent microorganisms.
CELLULAR BOUNDARIES Cell Wall – supports, shapes, and protects the
cell Allow water, oxygen, carbon dioxide to pass through Found in prokaryotes and eukaryotes (NOT ANIMALS) Provides strength in plants (wood is made of mostly
cell walls) Cell Membrane – controls what enters and
leaves the cell and supports Made of a lipid bilayer (see the next slide)
CELLULAR BOUNDARIES
The cell membrane is made of a double layered sheet with lipids and proteins
The cell membrane is selectively permeable – some substances are allowed to pass and some are not.
PLANT VS ANIMAL CELLS PG 206
7.3 CELL TRANSPORT
Passive Transport = The movement of materials across the cell membrane without using cellular energy is called passive transport. Diffusion - The process by which particles move from an
area of high concentration to an area of lower concentration
PASSIVE TRANSPORT CONT.
Facilitated Diffusion – the process where molecules that cannot directly diffuse across the membrane pass through special protein channelsOsmosis –the diffusion of water
through a selectively permeable
membrane
Water moves across a membrane
until equilibrium is reached
OSMOSISTypes of Solutions Isotonic = When the concentration is the same on both
sides of the membrane Hypertonic = The more concentrated solution Hypotonic = The dilute solution Osmotic pressure = the net movement of water out of or
into a cell exerts a force
ACTIVE TRANSPORT
Active transport = the movement of materials against a concentration difference (requires energy
MOVEMENT OF LARGE MOLECULES
CHAPTER 9 – ENERGY AND EXERCISE (PG 265)
Your body uses energy in the form of ATP Quick energy
First few seconds (50 m of a race) – use ATP stored in cells
Up to 90 seconds (200-300 m) – lactic acid fermentation (make lactic acid – to get rid of it, you need oxygen = breathing hard)
Long-term energy Over 90 seconds – cellular respiration glycogen (carbohydrate stores) are used up in 15-20 minutes followed by other molecules including fats.
CHOOSE THE CORRECT ORGANELLE
1. A.NucleusB.Nuclear
MembraneC.NucleolusD.GolgiE.Smooth ERF. Rough ER
2.
3.
4.
CHOOSE THE CORRECT LETTER
5. 6.
7.
8.
9. 10.
A.VacuoleB.ChloroplastC.CytoplasmD.Cell WallE.Cell MembraneF.Mitochondria
MATCH THE STRUCTURE AND FUNCTION
11. Controls what enters and leaves the cell
12. Gives support to cells, found in plants
13. Contains genetic material in the form of DNA and controls many of the cells activities
14. Makes ribosomes15. fluid portion of the cell
outside the nucleus.16. Controls what goes in and
out of the nucleus
A.NucleusB.Nuclear
MembraneC.NucleolusD.CytoplasmE.Cell WallF.Cell
Membrane
MATCH THE STRUCTURE AND FUNCTION
17. Storage18. Breaks down “old junk”19. “Protein factory”20. Membrane that has
ribosomes on it – makes proteins
21. Membrane that does not have ribosomes – makes lipids
22. modifies, sorts and packages proteins and other materials
A.RibosomesB.Smooth ERC.Rough ERD.Golgi BodiesE.VacuoleF.Lysosome
MATCH THE STRUCTURE TO THE FUNCTION
23. A cell with a nucleus
24. A cell without a nucleus
25. The “power house”
26. Structures in the nucleus made of DNA
27. Convert energy in sunlight to food
A.MitochondrionB.ChloroplastC.ChromosomesD.ProkaryoteE.Eukaryote