Introduction to Cells and cellular structures

CELL THEORY  A theory resulting from many scientists’ observations & conclusions Sch wan n Sch leid en Virc how

CELL THEORY 1. The basic unit of life is the cell. (Hooke)  In 1665, Robert Hooke made an improved microscope and viewed thin slices of cork wherein he saw plant cell walls.  Hooke named what he saw "cells"

CELL THEORY 2. All living things are made of 1 or more cells.  Matthias Schleiden (botanist studying plants)  Theodore Schwann (zoologist studying animals) stated that all living things were made of cells Schleiden Schwann

CELL THEORY 3. All cells divide & come from old cells. (Remak and virchow) Robert Remak was a Jewish biologist who researched cell division in frog eggs. Virchow was a German professor who claimed much of Remak’s work as his own.

“Cell Structure”

Cell Parts  Eukaryotic cells contain specialized structures called “organelles” or little organs.

 protects the cell  gives shape  is made of cellulose  A cell wall is found in plants, algae, fungi, & most bacteria. CELL WALL

CELL MEMBRANE  Outer covering, protective layer around ALL cells  For cells with cell walls,the cell membrane is inside the cell wall  Allows food, oxygen, & water into the cell & waste products out of the cell.

CYTOPLASM  gelatin-like inside cell membrane  constantly flows  Helps to keep organelles in place

CYTOSKELETON  scaffolding-like structure in cytoplasm  helps the cell maintain or change its shape  made of protein  Made of microtubules & microfilaments

NUCLEUS  Directs all cell activities  Contains instructions for everything the cell does  These instructions are found on a hereditary material called DNA  Usually the largest organelle

NUCLEAR MEMBRANE  separates nucleus from cytoplasm  controls movement of materials in & out of nucleus

NUCLEOLUS  Aka “little nucleus”  Found in the nucleus  Ribosomes are made here!  Is not considered an organelle  Not enclosed

CHROMATIN  contains genetic code that controls cell  made of DNA & proteins

CHLOROPLASTS  Green organelles that make food  found only in plant cells

CHLOROPHYLL  A green pigment that gives leaves & stems their color  Captures sunlight energy that is used to produce food called glucose  Glucose is a type of sugar

MITOCHONDRIA  Organelles that release energy from food (glucose)  This energy is released by breaking down food into carbon dioxide  AKA the powerhouse b/c they release energy from food  Some muscle cells have 20,000 mitochondria  Cells near the skin have many less (few hundred)  The number varies by tissue and organism

Mitochondria

 Quick fact: In humans, Mitochondrial DNA is inherited from the mother only  Mitochondrial DNA from the male is destroyed at fertilization In animals, mtDNA inheritance varies

RIBOSOMES  Synthesize (make) proteins  Float freely or attached to the endoplasmic reticulum (ER)  Ribosomes are made in the nucleolus

ENDOPLASMIC RETICULUM  A series of folded membranes that move materials (proteins) around in a cell  like a conveyor belt  Smooth ER – ribosomes not attached to ER  Rough ER – ribosomes attached to ER

Rough Endoplasmic Reticulum  Involved with the production and processing of proteins In cells that produce an abundance of proteins, there are many rough ER  It is connected to the nuclear envelope Result: the nucleus has direct access to proteins and other materials

Smooth Endoplasmic Reticulum  Many different functions depending on cell type  Contain a collection of enzymes that perform specialized tasks

GOLGI BODIES (GAWL jee)  Stacked flattened membranes  Sort and package proteins  Transforms proteins into more complex molecules

GOLGI BODIES (GAWL jee)

VACUOLES  Temporary storage spaces  Store food, water, waste

LYSOSOMES (LI suh sohmz)  The word "lysosome" is Latin for "kill body."  The purpose of the lysosome is to digest things. They might be used to digest food or break down the cell when it dies.  Break down food molecules, cell wastes & worn out cell parts  Lysosomes are built in the golgi apparatus

FROM CELL TO ORGANISM Cell The basic unit of life Tissue Group of cells working together Organ Group of tissues working together Organism Any living thing made of 1 or more cells Organ System Group of organs working together

NAME THE ORGANELLE d. Mitochondria b. Chloroplast c. Golgi bodya. Nucleus

1- Nucleus 2- Chromosomes 3- Mitochondria 4- Ribosomes 5- Chloroplasts 6- Vacuoles 7- ER 8- Cell Membrane