cell structure & function by back sroke @scie nobel prize & cell chemistry physiology or...

Cell Structure & Function

By Back Sroke @SCIE

Nobel Prize & Cell Chemistry Physiology or medicine

2010 Telomeres (DNA)

2009 RNA Viruses & Caner

2008

2007 Stem cell

2006 RNA RNA

2005 Viruses & diseases

2004 Protein

2003 Cell membrane

2002 Programmed cell death

2001 Cell Cycle

2000 Nerve signal

Organisms are made up of cells

Cell Theory• All living things are made up of cells.

• Cells are the basic units of all living things.

• All cells come from pre-existing cells through cell division.

Microscopes

Definition of Cell

A cell is the smallest unit that is capable of performing life

functions.

The size

REVIEW

• List one key point from the cell theory

• What is the definition of a cell?

• What instrument do you use for looking at cells?

Animal cell anatomy

“Typical” Animal Cell

REVIEW• List one main difference between plant

and animal cells

• Do plant and animal cells have organelles?

• What is the function of organelles?

Plant cell anatomy

“Typical” Plant Cell

REVIEW

• What are the main similarities and differences between plant and animal cells?

Cell PartsOrganelles

Surrounding the Cell

Cell Membrane structure

lipid “tail”

phosphate“head”

• Double layers of fat phospholipid bilayer

• Receptor molecule proteins that receive signals

• Carrier proteins Carry ions in and out of the

cell

Cell Membrane structure

• separates cell from outside

• controls materials in and out of the cell O2, CO2, food, H2O, nutrients, waste

• recognizes signals from other cells allows communication between cells

Cell Wall

• Most commonly found in plant cells & bacteria

• Supports & protects cells

• Cellulose cell wall

REVIEW

• Which structure surrounds a cell?

• The functionos of the cell surface membrane?

• The structure of the cell surface membrane?

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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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Inside the Cell

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OrganellesOrganelles

• Very small (Microscopic)

• Perform various functions for a cell

• Found in the cytoplasm

• May or may not be membrane-bound

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Animal Cell OrganellesAnimal Cell Organelles

Nucleolus

Nucleus

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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• Jelly-like substance enclosed by cell membrane

• Provides a medium for chemical reactions to take place

Cytoplasm of a CellCytoplasm of a Cell

cytoplasm

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• Contains organelles to carry out specific jobs

• Found in ALL cells

More on CytoplasmMore on Cytoplasmcytoplasm

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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 - NucleusThe Control Organelle - Nucleus

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• Each cell has fixed number of chromosomes that carry genes

• Genes control cell characteristics

Nucleus

More on the NucleusMore on the Nucleus

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Inside the Nucleus -The genetic material (DNA) is

found

DNA is spread out And appears as

CHROMATINin non-dividing cells

DNA is condensed & wrapped around proteins forming

as CHROMOSOMES in dividing cells

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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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MITOCHONDRIA

Surrounded by a DOUBLE membrane

(increases surface areafor more chemical Reactions)

Has its own DNA

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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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Rod shape

Cell PowerhouseCell Powerhouse

Mitochondrion( mitochondria )

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What do mitochondria do?What do mitochondria do?

Burns glucose to release energy (ATP)

Stores energy as ATP

“ Power plant” of the cell

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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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VacuolesVacuoles

• In plants, they store Cell Sap

• Includes storage of sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes

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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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ChloroplastsChloroplasts

• Contains its own DNA

• Contains enzymes & pigments for Photosynthesis

• Never in animal or bacterial cells

• Photosynthesis – food making process

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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?

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Cell Size• When the surface area is no longer great

enough to get rid of all the wastes and to get in enough food and water, then the cell must divide

• Therefore, the cells of an organism are close in size

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Cell SizeQuestion:

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!

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