question of the day this organelle is the powerhouse of the cell a. vacuole b. golgi apparatus c....

Question of the Day

• This organelle is the powerhouse of the cell

• A. Vacuole

• B. Golgi Apparatus

• C. Mitochondria

• D. Centriole

04/21/23 Template copyright www.brainybetty.com 2005 1

DOW NOW Oct 15

• Discuss Chapter 7 Project – The Cell Booklet

• See Project Requirements

• Textbooks with you at all times.

• We will be using them throughout this chapter.


CELL BOOKLET PROJECTOrganelle Pages

• 1. Ribosomes• 2. Endoplasmic Reticulum• 3. Golgi Apparatus• 4. Lysosomes• 5. Vacuoles• 6. Mitochondria• 7. Chloroplast• 8. Cytoskeleton• Include any other structures found within

these organelles (Bold print Terms)


AGENDA Oct 15

• BIG QUESTION: What is the cell theory?

• 1. QoD

• 2. DO NOW

• 3. Test

• 4. Begin Chapter 7 Section 1

• 5. 7-1 History of the Cell

• 6. Homework and Review04/21/23 Template copyright www.brainybetty.com 2005 4

Chapter 7Cell Structure and Function

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7-1: The Cell Theory• cells: the basic units of structure and

function in living things• discovery of the cell• Anton van Leeuwenhoek

– a Dutch biologist– invented

the first microscope

– studied drops of pond water and saw tiny living organisms


• Robert Hooke (1665)– observed cork– saw tiny, rectangular chambers which he

named cells– said plants only had cells

• Robert Brown (1833)– discovered the nucleus

• Matthias Schleiden (1838)– cell’s nucleus plays a role in reproduction

• Theodor Schwann (1839)– found animal tissues resembled plant

tissue– said animals were made of cells

• Rudolf Virchow (1855)– animal and plant cells are produced only

by the division of cells that already exist


The Cell Theory

• all living things are composed of cells

• cells are the basic units of structure and function in living things

• all cells come from preexisting cells


7-2: Cell Structure• cells range between 5 and 50

micrometers in diameter

• cells remain small because:– physical limits on the flow of information and

on the flow of material into and out of cell

• all cells have three basic structures:

– the cell membrane: the outer boundary of the cell

– the nucleus: control center of the cell

– the cytoplasm: material between the cell membrane and the nucleus



Cytoplasm

• area between the nucleus and the cell membrane

• fluid• contains many

important structures called organelles: tiny structures that performs a specialized function in the cell


Nucleus• controls the cell’s activities and contains DNA• prokaryotes: cells without a nucleus

– include bacteria• eukaryotes: cells with a nucleus• nuclear envelope: two membranes that surround the nucleus and

contain nuclear pores» nucleolus: found in the nucleus and made up of RNA

and proteins» makes ribosomes» chromosomes: found in the nucleus and contain the

genetic information


5-3: Cytoplasmic Organelles• 1. mitochondria: changes the

chemical energy stored in food into compound that the cell can use– contain two special

membranes• 2. chloroplast: trap the energy

of sunlight and convert it into chemical energy– only in plant cells and algae– structure similar to

mitochondria– has a second membrane to

change light energy into chemical energy

• reactions in both of these organelles are closely related


3. Ribosomes• structures in which

proteins are made• composed of RNA

and protein• some are attached to

membranes• some are found free

in the cytoplasm• smallest organelle• made in the nucleolus


4. Endoplasmic Reticulum• complex network of sacs that transports

material through the inside of the cell• two types

– smooth ER: does not have ribosomes attached

– special enzymes and chemicals are stored here

– rough ER: has ribosomes attached

– synthesizes proteins


5. Golgi Apparatus• special compartments that

modify proteins using special enzymes that attach carbohydrates and lipids

• looks like a flattened stack of membranes piled on top of each other

• modifies, collects, packages,and distributes molecules made at one location in the cell and used at another


6. Lysosomes• small membrane-bordered

structures that contain chemical and enzymes necessary for digesting materials in the cell that are taken in through endocytosis

• engulfing materials that are too large to pass through the cell membrane

• formed by the golgi apparatus

• plant cells do not have lysosomes

• cell’s cleanup crew


7. Vacuoles• saclike structures that store

materials such as water, salts, proteins, and carbohydrates

• plant cells have single large central vacuoles

• allows plants to grow quickly and gives extra support

• plastids: plant organelles that may take many forms

• one is the chloroplast• involved in storage of food

and pigments• leukoplast: store starch

granules• chromoplasts: store pigments


8. Cytoskeleton

• composed of a variety of filaments and fibers that support cell structure and drive cell movement

• microtubules: hollow and made of proteins

• provide support, help move organelles, and help in cell division

• microfilaments: long, thin fibers that function in movement and support

• help movement of cytoplasm called cytoplasmic streaming

Centrioles (See Cytoskeleton in your textbook)

• aid the cell in cell division

• arranges the microtubules of the cytoskeleton

• only found in animal cells

• found in pairs

7-3 Movement of Materials The Cell Membrane

• separates the cell from its surroundings• regulates what enters and leaves the cell• aids in the protection and support of the cell• communicates with other cells, takes in food

and water, and eliminates wastes• composed of a double layer of lipids, known

as a bilayer• contain proteins• act as channels through which molecules

pass or pumps to push molecules through• carbohydrates are also attached to proteins

or lipids and act like identification cards


Cell Wall• cell structure that surrounds the cell

membrane for protection and support• found in plants, algae, and some bacteria• very porous and allows water, oxygen,

carbon dioxide, and other substances through

• made up of two or more layers– a gluey substance called pectin: helps

hold the cells together– a fibrous material called cellulose: makes

the wall elastic so it can stretch and grow– in plants that contain wood, there is lignin:

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Diffusion

• diffusion: process by which molecules move from areas of higher concentration to areas of lower concentration

• equilibrium occurs when the concentrations on both sides of the membrane are the same

• permeability determines which substances move across the membrane


Osmosis• diffusion of water

molecules through a selectively permeable membrane

• pass through rapidly• moves from an area

of lower concentration to an area of higher concentration

• osmotic pressure: water pressure

• cells protect themselves with:

• cell walls • bathing cells in blood • contractile vacuoles

to pump out water


Facilitated Diffusion• some molecules are too large to pass

through cell membrane• molecules too large must pass through

a protein channel embedded in the cell membrane

• still driven by diffusion


Active Transport• requires energy • allows material to move against a

concentration difference• two types:

– carried through membrane-associated pumps (proteins)

– large amounts of material are transported through movements of the cell membrane

• endocytosis• phagocytosis: extensions of

cytoplasm surround and engulf large particles

• pinocytosis: pockets form along the membrane, fill with liquid, and pinch off to form vacuoles

• exocytosis: the removal of large molecules from the cell


7-4 Cell Specialization• uniquely suited to perform a

particular function within the organism

• two examples:• light sensitive cells

– packed with mitochondria– contains rhodopsin: a

pigment that absorbs light

• street sweepers– special cells line lung

passageways and release mucus

– particles are trapped in mucus

– have cilia


5-6: Levels of Organization• cells: basic unit of life• tissues: group of similar

cells that perform similar functions

• organs: a group of similar tissues that perform similar functions

• organ systems: group of similar organs that perform similar functions– muscular, skeletal,

digestive, circulatory, etc.

question of the day this organelle is the powerhouse of the cell a. vacuole b. golgi apparatus c....

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