MCAS Review Cell Biology. 2 Simple or Complex Cells copyright cmassengale.

MCAS Review

Cell Biology

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Simple or Complex Simple or Complex CellsCells

copyright cmassengale

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Prokaryotes – The first CellsProkaryotes – The first Cells

• Cells that lack a nucleus or membrane-bound organelles

• Includes bacteria• Simplest type of cell• Single, circular chromosome


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ProkaryotesProkaryotes

• Nucleoid region (center) contains the DNA

• Surrounded by cell membrane & cell wall (peptidoglycan)

• Contain ribosomes (no membrane) in their cytoplasm to make proteins


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Eukaryotes

• Cells that HAVE a nucleus and membrane-bound organelles

• Includes protists, fungi, plants, and animals

• More complex type of cells


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Two Main Types of Eukaryotic Cells

Plant Cell

Animal Cell


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Animal Cell OrganellesAnimal Cell Organelles

NucleolusNucleus

Nuclear envelope

Ribosome (attached)Ribosome (free)

Cell Membrane

Rough endoplasmic reticulum

Golgi apparatus

Mitochondrion

Smooth endoplasmicreticulum

Centrioles


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Plant Cell OrganellesPlant Cell Organelles


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Cell or Plasma MembraneCell or Plasma Membrane

Outsideof cell

Insideof cell(cytoplasm)

Cellmembrane

Proteins

Proteinchannel Lipid bilayer

Carbohydratechains

• Composed of double layer of phospholipids and proteins

• Surrounds outside of ALL cells• Controls what enters or leaves the cell• Living layer


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The Cell Membrane is The Cell Membrane is FluidFluid

Molecules in cell membranes are constantly moving and changing


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Cell Membrane ProteinsCell Membrane Proteins

• Proteins help move large molecules or aid in cell recognition

• Peripheral proteins are attached on the surface (inner or outer)

• Integral proteins are embedded completely through the membrane


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Recognize “self”

GLYCOPROTEINSGLYCOPROTEINS

Glycoproteins have carbohydrate tails to act as markers for cell recognition


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• Lies immediately against the cell wall in plant cells

• Pushes out against the cell wall to maintain cell shape

Cell Membrane in PlantsCell Membrane in PlantsCell membrane


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• Nonliving layer• Found in plants, fungi, &

bacteria• Made of cellulose in

plants• Made of peptidoglycan

in bacteria• Made of chitin in Fungi

Cell wallCell WallCell Wall


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Cell WallCell Wall• Supports and protects

cell• Found outside of the cell

membrane


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•Jelly-like substance enclosed by cell membrane

•Provides a medium for chemical reactions to take place

•Found in ALL Cells

Cytoplasm of a Cytoplasm of a Cell Cell

cytoplasm


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• Controls the normal activities of the cell

• Contains the DNA in chromosomes

• Bounded by a nuclear envelope (membrane) with pores

• Usually the largest organelle

The Control Organelle - The Control Organelle - NucleusNucleus


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Nuclear EnvelopeNuclear Envelope

• Double membrane surrounding nucleus

• Also called nuclear membrane• Contains nuclear pores for

materials to enter & leave nucleus• Connected to the rough ER

Nuclear pores


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CytoskeletonCytoskeleton• Helps cell maintain cell shape• Also help move organelles

around• Made of proteins• Microfilaments are

threadlike & made of ACTIN• Microtubules are tubelike &

made of TUBULIN


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CytoskeletonCytoskeleton

MICROTUBULES

MICROFILAMENTS


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CentriolesCentrioles• Found only in animal

cells• Paired structures near

nucleus• Made of bundle of

microtubules• Appear during cell

division forming mitotic spindle

• Help to pull chromosome pairs apart to opposite ends of the cell


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Centrioles & the Mitotic Centrioles & the Mitotic SpindleSpindle

Made of MICROTUBULES (Tubulin)


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MitochondrionMitochondrion(plural = mitochondria)(plural = mitochondria)

• “Powerhouse” of the cell• Generate cellular energy (ATP)• More active cells like muscle

cells have MORE mitochondria• Both plants & animal cells have

mitochondria• Site of CELLULAR RESPIRATION

(burning glucose)


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MITOCHONDRIASurrounded by a DOUBLE

membrane

Folded inner membrane called CRISTAE (increases surface areafor more chemical Reactions)

Has its own DNA

Interior called MATRIXcopyright cmassengale

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Interesting Fact ---Interesting Fact ---

• Mitochondria Come from cytoplasm in the EGG cell during fertilization

Therefore …• You inherit your

mitochondria from your mother!


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What do mitochondria What do mitochondria do?do?

Burns glucose to release energy (ATP)

Stores energy as ATP

“Power plant” of the cell


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Endoplasmic Reticulum - EREndoplasmic Reticulum - ER

Two kinds of ER ---ROUGH & SMOOTH

• Network of hollow membrane tubules• Connects to nuclear envelope & cell membrane• Functions in Synthesis of cell products & Transport


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Rough Endoplasmic Reticulum Rough Endoplasmic Reticulum (Rough ER)(Rough ER)

• Has ribosomes on its surface

• Makes membrane proteins and proteins for EXPORT out of cell


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Smooth Endoplasmic ReticulumSmooth Endoplasmic Reticulum

• Smooth ER lacks ribosomes on its surface

• Is attached to the ends of rough ER

• Makes cell products that are USED INSIDE the cell


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Functions of the Smooth Functions of the Smooth ERER• Makes membrane

lipids (steroids)• Regulates calcium

(muscle cells)• Destroys toxic

substances (Liver)


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RibosomesRibosomes• Made of PROTEINS and rRNA• “Protein factories” for cell• Join amino acids to make proteins• Process called protein synthesis


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RibosomesRibosomes

Can be attached to Rough ER

OR

Be free (unattached) in the cytoplasm


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Golgi BodiesGolgi Bodies• Stacks of Stacks of flattened sacsflattened sacs• Have a shipping side (Have a shipping side (trans trans

faceface) and receiving side () and receiving side (cis cis faceface))

• Receive Receive proteinsproteins made by ER made by ER• Transport vesiclesTransport vesicles with with

modified proteins pinch off modified proteins pinch off the endsthe ends

Transport vesicle

CIS

TRANS


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Golgi BodiesGolgi Bodies

Look like a stack of pancakes

Modify, sort, & packagemolecules from ERfor storage OR transport out of cell


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Golgi AnimationGolgi Animation

Materials are transported from Rough ER to Golgi to the cell membrane by VESICLES


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LysosomesLysosomes• Contain Contain digestive enzymesdigestive enzymes• Break down Break down food, bacteria,food, bacteria,

and and worn out cell partsworn out cell parts for for cells cells

• Programmed forProgrammed for cell death cell death (AUTOLYSIS)(AUTOLYSIS)

• Lyse (break open) & Lyse (break open) & release enzymesrelease enzymes to break to break down & recycle cell parts)down & recycle cell parts)


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Lysosome DigestionLysosome Digestion

• Cells take in food by phagocytosis

• Lysosomes digest the food & get rid of wastes


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Cilia & FlagellaCilia & Flagella

• Made of protein tubes called microtubules

• Microtubules arranged (9 + 2 arrangement)

• Function in moving cells, in moving fluids, or in small particles across the cell surface


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Cilia & FlagellaCilia & Flagella

• Cilia are shorter and more numerous on cells

• Flagella are longer and fewer (usually 1-3) on cells


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Cell Movement with Cilia & Cell Movement with Cilia & FlagellaFlagella


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Cilia Moving Away Dust Particles from Cilia Moving Away Dust Particles from the Lungsthe Lungs

Respiratory SystemRespiratory System


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VacuolesVacuoles• Fluid filled sacks

for storage• Small or absent in

animal cells• Plant cells have a

large Central Vacuole

• No vacuoles in bacterial cells


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Contractile VacuoleContractile Vacuole

• Found in unicellular protists like paramecia

• Regulate water intake by pumping out excess (homeostasis)

• Keeps the cell from lysing (bursting)

Contractile vacuole animation


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ChloroplastsChloroplasts• Found only in producers

(organisms containing chlorophyll)

• Use energy from sunlight to make own food (glucose)

• Energy from sun stored in the Chemical Bonds of Sugars


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ChloroplastsChloroplasts• Surrounded by DOUBLE

membrane• Outer membrane smooth• Inner membrane modified into

sacs called Thylakoids• Thylakoids in stacks called

Grana & interconnected• Stroma – gel like material

surrounding thylakoids


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Cell Size

Question:Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse?


Factors Affecting Cell Size

• Surface area (plasma membrane surface) is determined by multiplying length times width (L x W)

• Volume of a cell is determined by multiplying length times width times height (L x W x H)

• Therefore, Volume increases FASTER than the surface area


• DNA Overload = Not enough DNA to direct the whole cell


• Movement of materials into and out of the cell

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Cell Size

Question:Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse?

About the same size, but …

The elephant has MANY MORE cells than a mouse!


Cell Transport

Plasma Membrane

• Selectively permeable barrier

– Allows nutrients in

– Waste can go out

Passive Transport

Uses NO Energy

Types of Passive Transport(No ATP)

• Diffusion: – Kinetic Energy – Down or with

Concentration Gradient– Molecules must be small

or fat soluble to get across membrane

– Can be either direction– Heat Increases Speed

• Examples: fats, fat soluble vitamins, O2, CO2 or small ions like chloride (Cl-)

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DIFFUSIONDIFFUSION

Diffusion is a PASSIVEPASSIVE process which means no energy is used to make the molecules move, they have a natural KINETIC ENERGY


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Diffusion of LiquidsDiffusion of Liquids


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Diffusion through a MembraneDiffusion through a Membrane

Cell membrane

Solute moves DOWN concentration gradient (HIGH to LOW)copyright cmassengale

Types of Passive Transport

• Osmosis

– The diffusion of water– Polar, but can move through aquaporins made by

proteins in the membrane– Moves down or with concentration gradient– Can be either direction

• Example: Only Water

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Diffusion of HDiffusion of H22O Across A O Across A MembraneMembrane

High H2O potentialLow solute concentration

Low H2O potentialHigh solute concentration


• Facilitated Diffusion:

– Large Molecules or Lipid-insoluble– Down or with the concentration gradient– Protein channel is needed– Either direction

• Example: Glucose

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AquaporinsAquaporins• Water Channels• Protein pores used during OSMOSISWATER

MOLECULES


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Cell in Isotonic SolutionCell in Isotonic Solution

CELLCELL

10% NaCL90% H2O

10% NaCL

90% H2O

What is the direction of water movement?The cell is at _______________.equilibrium

ENVIRONMENTENVIRONMENT

NO NET NO NET MOVEMENTMOVEMENT


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Cell in Hypotonic SolutionCell in Hypotonic Solution

CELLCELL

10% NaCL90% H2O

20% NaCL

80% H2O

What is the direction of water movement? copyright cmassengale

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Cell in Hypertonic SolutionCell in Hypertonic Solution

CELLCELL

15% NaCL85% H2O

5% NaCL95% H2O

What is the direction of water movement?

ENVIRONMENTENVIRONMENT


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Cells in SolutionsCells in Solutions


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Cytolysis & PlasmolysisCytolysis & Plasmolysis

Cytolysis Plasmolysis


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Osmosis in Red Blood CellsOsmosis in Red Blood Cells

Isotonic Hypotonic HypertonicIsotonic Hypotonic Hypertonic

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hypotonic hypertonic isotonic

hypertonic isotonic hypotonic



• Filtration:

– Uses pressure gradient (fluid or hydrostatic)– Filtrate goes from high to low pressure through a

membrane or capillary

• Example: water and solutes filter through kidneys

Active TransportRequires ATP

Active Transport (ATP)

• Solute Pump– ATP energizes protein carriers embedded in

membrane– Against the concentration or electrical gradient– Large or not lipid soluble molecules

• Examples: Amino Acids – Large MoleculeSodium-Potassium Pump - ATP is needed to pump sodium out of cell where there is more sodium and potassium that leaks out of the cell has to be pumped back inside.

Active Transport uses ATP for Bulk Transport

• Exocytosis:– Out of the cell– Transport vesicle (packaged by Golgi)– Migrates to membrane– Fuses and then empties outside cell

• Examples: Secreting hormones, mucus, cellular waste

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Moving the “Big Stuff”Moving the “Big Stuff”

Molecules are moved out of the cell by vesicles that fuse with the Molecules are moved out of the cell by vesicles that fuse with the plasma membrane.plasma membrane.

ExocytosisExocytosis-

moving things out.

This is how many hormones are secreted and how nerve cells This is how many hormones are secreted and how nerve cells communicate with one anothercommunicate with one another.

Active Transport uses ATP for Bulk Transport

• Endocytosis– Into the cell– Engulfing extra-cellular substances– Forms a sac around the substance – Pulls it in and the sac buds off– Fuses with a lysosome– Enzymes digest the contents

Types of Endocytosis

• Phagocytosis: Cellular eating. Ex: White blood cells get rid of bacteria. Protective

• Pinocytosis: Absorption function, droplets are surrounded and taken in. Ex: dissolved protein or fat

• Receptor-mediated:Taking up target molecules, proteins bind only with certain molecules. Ex: hormones, cholesterol, iron and sometimes viruses get in this way

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PhagocytosisPhagocytosis

Used to Used to engulf large particles engulf large particles such as food, such as food, bacteriabacteria, etc. into vesicles, etc. into vesicles

Called Called ““Cell EatingCell Eating””copyright cmassengale

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PinocytosisPinocytosis

Most Most commoncommon form of endocytosisform of endocytosis.

Takes in Takes in dissolveddissolved molecules as a vesicle molecules as a vesicle. copyright cmassengale

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Receptor-Mediated EndocytosisReceptor-Mediated Endocytosis

Some Some integral proteins integral proteins have have receptorsreceptors on their on their surface to recognize & take in surface to recognize & take in hormones, hormones, cholesterolcholesterol, etc., etc.


A. growth of the cell

B.replication of the DNA

C.formation of the mitotic spindle

D.breakdown of the nuclear membrane

The diagram shows the cell cycle. Which of the following activities occurs in the G1 phase?

A. growth of the cell B.

C.

D.

The diagram shows the cell cycle. Which of the following activities occurs in the G1 phase?

A. a bacterium

B. a fungus

C. a protist

D. a virus

A researcher is studying a particular disease-causing agent. The agent has a protein coat, but it lacks a nucleus, contains no other organelles, and can reproduce only when it is inside an animal cell. The researcher should classify the agent as which of the following?

A.

B.

C.

D. a virus

A researcher is studying a particular disease-causing agent. The agent has a protein coat, but it lacks a nucleus, contains no other organelles, and can reproduce only when it is inside an animal cell. The researcher should classify the agent as which of the following?

Dye Test

acridine orange stains DNA and RNA

osmium tetroxide stains lipids

eosin stains cell cytoplasm

Nile blue stains cell nuclei

A. acridine orange

B. osmium tetroxide

C. eosin

D. Nile blue

A lab technician needs to determine whether cells in a test tubeare prokaryotic or eukaryotic. The technician has several dyes she could use to stain the cells. Four of the dyes are described in the table below.Which dye could the technician use to determine whether the cells are prokaryotic or eukaryotic?

Dye Test

acridine orange stains DNA and RNA

osmium tetroxide stains lipids

eosin stains cell cytoplasm

Nile blue stains cell nuclei

A.

B.

C.

D. Nile blue

A lab technician needs to determine whether cells in a test tubeare prokaryotic or eukaryotic. The technician has several dyes she could use to stain the cells. Four of the dyes are described in the table below.Which dye could the technician use to determine whether the cells are prokaryotic or eukaryotic?

A.The cell would produce more proteins than it needs.

B.The cell would have chloroplasts that appear yellow rather than green.

C.The cell would be less able to break down molecules in its cytoplasm.

D.The cell would be less able to regulate the amount of fluid in its cytoplasm.

If a cell’s lysosomes were damaged, which of the following would most likely occur?

A. active transport

B. enzyme activity

C. osmosis

D. respiration

If an animal cell is placed in distilled water, it will swell and burst. The bursting of the cell is a result of which biological process?

Scientists believe that the first organisms that appeared on Earth were prokaryotic. Which of the following best represents what the cell structure of these organismsmay have looked like?

Scientists believe that the first organisms that appeared on Earth were prokaryotic. Which of the following best represents what the cell structure of these organismsmay have looked like? No Nucleus

A. Cell X is a prokaryotic cell and cell Y is a eukaryotic cell.

B. Cell X is an archae cell and cell Y is a eubacterial cell.

C. Cell X is a red blood cell and cell Y is a muscle cell.

D. Cell X is a plant cell and cell Y is an animal cell.

The illustrations below represent two different cells.

Which of the following statements best Identifies these two cells?

The diagram below shows a cross section of part of a cell membrane.

a. Describe the basic structure of the cell membrane.

b. Describe two primary functions of the cell membrane.

c. Explain how the structure of the cell membrane allows it to perform the functions described in part (b).

A. Describe the basic structure of the cell membrane.

• A.) The cell membrane is made up of 2 layers of phospholipids. The hydrophyllic heads point outward, while the hydrophobic tails point inward. This is because the cytoplasm inside the cell and the fluid outside the cell contain water. Proteins can also be found in the membrane and their function is to facilitate diffusion, to act a s a pump, or as identifying markers.

B. Describe two primary functions of the cell membrane.

• B) The primary functions of the cell membrane are, first, to maintain a boundary that keeps the organelles and cytoplasm inside and the other particles outside. Second, the membrane is selectively permeable allowing nutrients in and waste products out as well as protecting the cell.

C. Explain how the structure of the cell membrane allows it to perform the

functions described in part (B).• C.) The structure of the cell membrane allows

it to perform its functions. The lipid bilayer forms a strong flexible barrier between the cell and its surroundings which repels water and large molecules. The protein molecules embedded in the bilayer act as channels or pumps to allow certain molecules in or out of the cell. In addition, some of the proteins have carbohydrate chains attached that act as identification markers.

Which of the following functions does active transport perform in a cell?

A. packaging proteins for export fromthe cell

B. distributing enzymes throughout thecytoplasm

C. moving substances against aconcentration gradient

D. equalizing the concentration of waterinside and outside the cell

Which of the following is a mainfunction of the cell wall?

A. to store carbohydrates for later useB. to give the cell a rigid structureC. to package proteins for exportD. to carry out photosynthesis

Which of the following statementscorrectly matches a cell part with

its function?

A. The cell membrane packages lipidsfor export

B. The mitochondria performphotosynthesis.

C. The lysosome digests molecules.D. The nucleus produces energy.

The drawing below represents an organism that a student observed when examining a sample of pond

water with a light microscope.

• The student identified this organism as a prokaryote.

• A.) Is the student's identification accurate? Explain your answer using information from the diagram.

• B.) Identify three similarities between the cells of prokaryotes and eukaryotes.

A.) Is the student's identification accurate? Explain your answer using information from the diagram.

• No, the student is not correct. This organism has a nucleus and membrane bound organelles, a prokaryote does not have these things.

B.) Identify three similarities between the cells of prokaryotes and eukaryotes.

• Three similarities between prokaryotes and eukaryotes are: 1.) Both have DNA which contains its genetic information. 2.) Both grow and reproduce and 3.) Both have a cell membrane

Some cells, such as human nerve and muscle cells, contain many more mitochondria than do other cells,

such as skin cells. Why do some cells have more mitochondria than others?

A. The cells use more energy.B. The cells store more nutrients.C. The cells degrade more proteins.D. The cells divide more frequently.

A single prokaryotic cell can divide several times in an hour. Few eukaryotic cells can divide as quickly.

Which of the following statements best explains this difference?

A.Eukaryotic cells are smaller than prokaryotic cells.B.Eukaryotic cells have less DNA than prokaryotic cells.C.Eukaryotic cells have more cell walls than prokaryotic cells.D.Eukaryotic cells are more structurally complex than prokaryotic cells.

The diagram below illustrates how plant root cells

take in mineral ions from the surrounding soil.• Which of the following

processes is illustrated?

A. Active transportB. DiffusionC. OsmosisD. Passive filtration

Which of the diagrams below best represents the net movement of molecules in osmosis?

• A.

• B.

• C.

• D.

A cross section of part of a Golgi complex is shown below.

Part of the membrane of the Golgi complex pinches off and moves away. Which of the following is a function of this process?

• A. to release energy from ATP

• B. to deliver proteins to other locations in the cell

• C. to collect amino acids for use in protein synthesis

• D. to send messages about cell requirements to the nucleus

MCAS Review Cell Biology. 2 Simple or Complex Cells copyright cmassengale.

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Transcript of MCAS Review Cell Biology. 2 Simple or Complex Cells copyright cmassengale.