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