The Cell n A cell is the smallest

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The Cell n A cell is the smallest unit of living matter. n Don’t

The Cell n A cell is the smallest unit of living matter. n Don’t confuse this with: atom, element, proton, etc.

Cell Size

Cell Size

Three Main Parts n Plasma membrane n Nucleus n Cytoplasm

Three Main Parts n Plasma membrane n Nucleus n Cytoplasm

These are ALL CELLS!

These are ALL CELLS!

Cell Theory n “Theory” is not a casual term in science. n Tested innumerable

Cell Theory n “Theory” is not a casual term in science. n Tested innumerable times with consistent results. n Universally accepted n One of the most basic, fundamental concepts in the foundation of biology.

Cell Theory – 1800 s; several scientists working independently had similar results. 1. All

Cell Theory – 1800 s; several scientists working independently had similar results. 1. All organisms are made of cells. 2. A cell is the structural & function unit of organs. 3. All cells come from pre-existing cells. 4. Cells are capable of self-reproduction.

There are two types of cells: Prokaryotic- cells that DO NOT have a nucleus

There are two types of cells: Prokaryotic- cells that DO NOT have a nucleus or other cell ORGANELLES 2. Eukaryotic- cells with a NUCLEUS & cell ORGANELLES 1. Which is more complicated? n REMEMBER YOU ARE EUKARYOTIC! n

Prokaryotic vs Eukaryotic n n n Pro = before Karyote=kernel(nucleus) DNA is NOT contained

Prokaryotic vs Eukaryotic n n n Pro = before Karyote=kernel(nucleus) DNA is NOT contained within a nucleus Most have a cell wall outside the plasma membrane May have type of flagella or pilus Archaea and Bacteria Eu= true n Karyote=nucleus n DNA contained in double membraned nucleus n Only plant cells have cell wall n Contains membrane bound organelles n Plants, animals, protists, fungi n

Types of Organisms n Unicellular organisms – Bacteria, Protists, etc. n Multicellular organisms –

Types of Organisms n Unicellular organisms – Bacteria, Protists, etc. n Multicellular organisms – Plants – Animals § Muscles, skin, nerves, liver, digestive, bones, blood, immune system, lungs, etc.

Why cells aren’t bigger n If cells get too large in volume compared to

Why cells aren’t bigger n If cells get too large in volume compared to their surface area then it’s difficult to distribute nutrients throughout the cell and too hard to get rid of build up of wastes.

The Cell Membrane A phospholipid bilayer With proteins embedded in it

The Cell Membrane A phospholipid bilayer With proteins embedded in it

Hydrophillic heads and Hydrophobic tails n The phospholipid consists of hydrophilic heads, which point

Hydrophillic heads and Hydrophobic tails n The phospholipid consists of hydrophilic heads, which point towards the outside environment and the cytoplasm. The hydrophobic tails repel the water and point in. Thus, the phospholipids form a bilayer that acts like a barrier between the cell and the environment. The phospholipid bilayer also contains cholesterol, which makes the bilayer stronger, more flexible and more permeable. There a number of important proteins in the plasma membrane

Fluid Mosaic Model of the Cell Membrane The purpose of the membrane is to

Fluid Mosaic Model of the Cell Membrane The purpose of the membrane is to control what goes in and out of the cell. n Semi-permeable means certain molecules can be transported across the membrane while others are kept out. n Proteins that are found in the bilayer are receptor proteins, which deal with communication, recognition proteins and transport proteins that regulate the movement of water and soluble molecules through the membrane. n

Transport of molecules across the membrane n Transport is either active or passive. n

Transport of molecules across the membrane n Transport is either active or passive. n Active transport is moving molecules against the concentration gradient and energy is required in the form of ATP. n Passive transport is moving molecules down the concentration gradient and no energy is required. – diffusion, which moves from high concentration to low concentration – osmosis, which is the diffusion of water molecules

Cell membrane interactive n cell membrane interactive n file: ///C: /Documents%20 and%20 Settings/ nancy/My%20

Cell membrane interactive n cell membrane interactive n file: ///C: /Documents%20 and%20 Settings/ nancy/My%20 Documents/tdc 02_int_mem braneweb/tdc 02_int_membraneweb. htmlfi le: ///C: /Documents%20 and%20 Settings/n ancy/My%20 Documents/tdc 02_int_membr aneweb/tdc 02_int_membraneweb. html

The Organelles n. . Desktoptdc 02_vid_organelles. zip

The Organelles n. . Desktoptdc 02_vid_organelles. zip

The Nucleus- DNA container

The Nucleus- DNA container

Nucleus n cellular control center – Controls cellular activity n contains hereditary material (DNA

Nucleus n cellular control center – Controls cellular activity n contains hereditary material (DNA in chromosomes) n self duplicating structure -divides when the cell divides

Structure of Nucleus n Nuclear Envelope (membrane): – Double lipid bilayer: keeps DNA separated

Structure of Nucleus n Nuclear Envelope (membrane): – Double lipid bilayer: keeps DNA separated from the rest of the cell – Continuous with Endoplasmic Reticulum n Nucleolus: assembly of ribosomes for protein synthesis n Nuclear pores: holes that allow stuff in and out

Endoplasmic Reticulum

Endoplasmic Reticulum

Rough Endoplasmic Reticulum n “HIGHWAY” for cell transport consists of a network of interconnected,

Rough Endoplasmic Reticulum n “HIGHWAY” for cell transport consists of a network of interconnected, flattened sacs whose walls are formed of a single membrane. The outer surface is "rough" because it is studded with small particles called ribosomes. n The ribosomes synthesize proteins and discharge them into the sacs where they are packaged in membranes which travel through the cytoplasm to other organelles……. n (GOLGI BODIES) where they are further processed. n

Golgi Bodies n Add carbohydrates component to the protein and package the finished product

Golgi Bodies n Add carbohydrates component to the protein and package the finished product before it leaves the cell. n Form the plasma membrane and membranes of lysosomes

Lysomes n produced by the Golgi apparatus n contain powerful protein digesting enzymes n

Lysomes n produced by the Golgi apparatus n contain powerful protein digesting enzymes n responsible for the breakdown and absorption of materials taken in by the cell. n Often, a cell engulfs a foreign substance through ENDOCYTOSIS, another form of active transport. During endocytosis, the cell membrane puckers up, forms a pouch around materials outside the cell, and pinches off to become a vesicle. If the contents need to be destroyed, lysosomes combine with the vesicle and release their enzymes.

vacuoles n n n n fluid-filled, membrane-surrounded cavities inside a cell. The vacuole fills

vacuoles n n n n fluid-filled, membrane-surrounded cavities inside a cell. The vacuole fills with food being digested and waste material that is on its way out of the cell. removing unwanted structural debris surrounding the cell sequestering materials that might be toxic to the cell containment of waste products maintaining internal hydrostatic pressure or turgor within the cell (especially plant cells) storing small molecules exporting unwanted substances from the cell.

vacuoles

vacuoles

Mitochondria n n n Mitochondria are the cells' power sources. They are distinct organelles

Mitochondria n n n Mitochondria are the cells' power sources. They are distinct organelles with two membranes. Usually they are rod-shaped, however they can be round. The outer membrane limits the organelle. The inner membrane is thrown into folds or shelves that project inward. These are called "cristae mitochondriales Contain their own DNA which can be passed on

Endosymbiosis n It is theorized that mitochondria and chloroplasts were once free living bacteria

Endosymbiosis n It is theorized that mitochondria and chloroplasts were once free living bacteria that got caught in evolution n Both are double membraned, contain their own DNA and can self replicate

Quick check What is meant by the phrase "the cell is the functional unit

Quick check What is meant by the phrase "the cell is the functional unit of life"? n How are the organelles in a cell like the organs in a human body? n Why do you think cells that produce large numbers of proteins have more rough endoplasmic reticulum (ER) than cells that produce fewer proteins? n In which kinds of human cells would you expect to find the most mitochondria? The most lysosomes? The most ribosomes? Explain your answers. n

centrioles

centrioles

Centrioles n Found only in animal cells, these paired organelles are typically located together

Centrioles n Found only in animal cells, these paired organelles are typically located together near the nucleus, n centrioles are positioned so that they are at right angles to each other, Each centriole is made of nine bundles of microtubules (three per bundle) arranged in a ring. n Centrioles play a notable role in cell division.

cytoskeleton ELEMENTS OF THE CYTOSKELETON All of the microfilaments and microtubules combine to form

cytoskeleton ELEMENTS OF THE CYTOSKELETON All of the microfilaments and microtubules combine to form the cytoskeleton of the cell. n The cytoskeleton is different from cytoplasm. The cytoskeleton provides structure. Cytoplasm is just a fluid. n The cytoskeleton connects to every organelle and every part of the membrane. Think about an amoeba. All of the pieces work together so that the foot might reach out towards the food. Then the lysosomes and peroxisomes are sent to begin digestion. The movement of the organelles and cytoplasm is all related to the tubules. n

Plant Cell

Plant Cell

Plant cell wall n n n rigidity of the cell wall renders plants sedentary

Plant cell wall n n n rigidity of the cell wall renders plants sedentary Made of Cellulose animals lack of wall allows their cells more flexibility, which is necessary for locomotion. protects the intracellular contents provides a porous medium for the circulation and distribution of water, minerals, and other nutrients, and houses specialized molecules that regulate growth and protect the plant from disease.

Cell wall n The main chemical components of the primary plant cell wall include

Cell wall n The main chemical components of the primary plant cell wall include cellulose (in the form of organized microfibrils; a complex carbohydrate made up of several thousand glucose molecules linked end to end.

Plant cell wall

Plant cell wall

Chloroplasts are specialized organelles found in all higher plant cells. These organelles contain the

Chloroplasts are specialized organelles found in all higher plant cells. These organelles contain the plant cell's chlorophyll, hence provide the green color. They have a double outer membrane. Within the stroma are other membrane structures - the thylakoids and grana (singular = granum) where photosynthesis takes place. n n

Chloroplasts

Chloroplasts

DIFFERENCES BTW PLANT AND ANIMAL CELLS n • • PLANT CELL Fixed structure. Has

DIFFERENCES BTW PLANT AND ANIMAL CELLS n • • PLANT CELL Fixed structure. Has a cellulose cell wall and a cell membrane Chlorophyll in chloroplasts large vacuoles n • • • ANIMAL CELL Can change shape. No Cellulose cell wall No Chlorophyll or chloroplasts Small or no vacuoles Has centrioles