life science chapter 3 cells. bellwork what do you know about cells?
TRANSCRIPT
Life Science
Chapter 3Cells
Bellwork
• What do you know about cells?
Characteristics of Living things
• What were they?
Cells
• All living things are made of cells• Bacteria and algae are unicellular
(one-celled)• People are made of millions of cells–Our cells organize themselves into
tissue, organs, and everything else, then linked together to make an organism
Cells
•Cells: The basic unit of structure in all living things-smallest unit in which life process can be carried out
Read
• Take about 5 minutes to read pages 47-49 about the advancements in science and technology
On your own
• Create a flow chart displaying the advancements in science and technology from Hans and Zacharias Jannsen (1590) to Rudolf Virchow (1902)
Cell theory flow chart
Jannsen brothers
• Invented the microscope
Scientist
• Discovery/invention
Scientist
• Discovery/Invention
Flow chart
Jannsen brothers 1590-1610
• Invented the microscope
Hooke 1665
• First to see cells, named after monks
Leeuwenhoek 1632-1723
• Saw structures in cells
Schleiden 1804-1881
• Found plants were made of cells too
Brown 1773-1858
• Observed nucleus in plant cells
Schwann 1810-1882
• Animal tissues made of cells too
Virchow
• All cells arise form preexisting cells
Cell Theory
• Cell theory: • All living things are composed of
one or more cells• A cell is the basic unit of life in all
living things-all chemical reactions of a living organism occur within its cells
Cell theory continued
• All cells come from other cells
Bellwork
•What is the job of a cell?
Size of cells
•Most cells are microscopic•An average cell is only one
ten-billionth of a gram•We have about 60 trillion
of these cells
Size of cells
• Some cells are bigger than others• The nerve cell in a giraffe’s leg
can be 3 meters long
Cell differences
• Plant cells are large and rectangular• Animal cells are small and oval
Cell differences
•Most cells have a nucleus•Bacteria lack this structure
Differences
• Some cells make up organisms• Some are the organism and
can move on their own
Similarities
• Cells have 75-85% water• The other 15-25% is fat,
sugars, and proteins• These ingredients carry out
billions of chemical reactions each minute.•
• Some provide support and protection, repair cells, store and release energy, transport materials, get rid of wastes, and reproduce
Cell video
• http://www.youtube.com/watch?v=o1GQyciJaTA
Read page 50-54
• Imagine that a cell is a small city.• For each job in the cell, think of a
real-life job that reasonably compares with the job of this cell part• Write each one out like an analogy
•When you complete the first activity,• Create your own animal cell• Draw one and label each part
listed in the reading.• Use the information in the
reading and the pictures to help you
Bellwork
•What are some differences between a plant cell and an animal cell?
Jobs of cells
•Cell wall: a thick outer layer of cellulose that gives plant cells added support and strength.
Cell wall
• Cellulose is a strong organic material that allows materials such as oxygen, carbon dioxide, and minerals to pass in and out of the cell• The stringy part of celery is
cellulose
Cell Membrane•Animal cells do not have
cell walls, they have Cell Membranes: a flexible, thin protective layer around a cell that helps to control what goes in and out of the cell
Cell membrane
•Not rigid like a plant cell wall, but still protects and supports the cell•Necessary materials enter
the membrane and wastes exit the membrane
Cytoplasm
•Cytoplasm: a watery fluid that surrounds everything in the cell
Organelles
•Cytoplasm is constantly moving and filled with organelles: structures inside a cell that perform a particular function for the cell
Nucleus
•Nucleus: the cell’s control center; it stores the cell’s genetic information and controls cell functions•Usually largest and most
visible organelle
Nuclear Membrane
• Nuclear Membrane/Envelope: Thin membrane around the nucleus• Lets materials in and out of the
nucleus• Filled with fluid and structures
called Chromosomes
Chromosomes
•Chromosomes: structures that direct cell growth and reproduction and hold the genetic information that is passed on to new cells
Chromosomes
•Because of chromosome controls, white blood cells reproduce white blood cells rather than skin or hair cells
Mitochondria
•Mitochondria: produce energy for the cell• They metabolize sugars into
eater and carbon dioxide• As they metabolize, they
release energy that the cell can use to do work
Mitochondria
• Active cells have more mitochondria than less active cells• One active cell may have 1000
mitochondria while a skin cell has only a few
Endoplasmic Reticulum (ER)
• ER: an organelle that functions as the cell’s transportation system.• ER is a system of tubes,
flattened sacs, and channels within the cytoplasm.
Bellwork
•What do you think is the most interesting organelle of the cell, why?
ER
• ER transports proteins and other substances throughout the cell• There are two types of ER:
•Rough ER which is studded with ribosomes•Smooth ER without ribosomes
Ribosomes• Ribosomes: tiny organelles that
produce protein for the cell• They can float through the
cytoplasm of the cell, then once they have produced protein they attach to the ER which then carries the protein throughout the cell
Golgi Apparatus
• Golgi Apparatus: organelle that modifies and transports proteins and lipids • Can also transport the proteins
made by ribosomes
Lysosomes
• Lysosomes: Organelles that recycle work-out cell organelles and metabolized material for the body to reuse• They pass this material on to
the mitochondria
Lysosome
• Lysosomes also destroy invaders such as bacteria• They are more common in
animal cells than plant cells
Vacoules
• Vacuoles: organelles that store water, food, materials cells need, and waste products.•When you water a plant, the
vacuoles fill up…that’s why they “plump” up
Chloroplasts
• Chloroplasts: only found in plant cells, are the metabolic centers that contain the green pigment chlorophyll.• They capture sunlight, which
the plants uses to make its own food
Assignment
•Complete the cell function worksheet front and back
• http://www.youtube.com/watch?v=JnlULOjUhSQ
• http://www.youtube.com/watch?v=pvOz4V699gk
Bellwork
• What was your favorite part about designing your cell? Write it please before we talk about it.
• *TEST next Monday!
Cell Energy• Cells need energy to live,
produce, and grow• Energy is the ability to do work•When you feel tired and
hungry, that is your body telling you that your cells need energy
Cellular Respiration
• Cellular Respiration: The breaking down of food molecules by cells into useable energy• Plants do this through
photosynthesis
Capture light energy from
the sun
Change carbon
dioxide and water into glucose
Use some glucose for food and store the
rest as starch
Produce the byproduct
oxygen
Glucose
• http://www.youtube.com/watch?v=OYH1deu7-4E
Cellular Respiration• In most cells, CR occurs in the
mitochondria• Materials are broken down to
simpler forms• The ATP (adenosine triphosphate)
is the molecule that carries this energy for cellular activity
Energy
•Most of this energy is released as heat that helps maintain body temperature
Metabolic Pathways
• Cells need energy to shuffle materials within a cell; they use metabolic pathways•Metabolic pathways: a series
of chemical reactions that break down or make materials that the cell needs
Metabolic Pathways
•Plant cells use metabolic pathways to build their cell walls
Metabolic Pathways
•Red blood cells have metabolic pathways that use energy to manufacture hemoglobin molecules (chains that transport oxygen through the blood)
Enzymes
•Many chemical reactions in cells involve enzymes• Enzymes are special
proteins that speed up chemical reactions in an organism or cell.
Enzymes
• http://www.youtube.com/watch?v=XTUm-75-PL4
Fermentation
• Sometimes cells can’t get enough oxygen for respiration to produce the high levels of ATP (remember this is what delivers the energy for the cell’s activities.
Fermentation
• Small amounts of ATP can be made through fermentation which breaks down glucose without oxygen