Organization of Living Systems

I. Characteristics of Life

What makes something alive?-has an orderly structure-reproduces-grows and develops-adjusts to changes in the

environment

Are these things alive?

Plant air windanimals

bacteria viruses protists

rocksfungi soil

fire water

Are these things alive?

Plant air windanimals

bacteria viruses protists

rocksfungi soil

fire water

Living

Living

Living

Living

Living

Ex. of Life and Nonlife:

Living Things: plants, animals, protists, fungi, bacteria

Nonliving Things: viruses, fire, rocks, soil, air, water, sunlight

This is a picture of Mycobacterium tuberculosis a bacteria which causes the disease tuberculosis. What happens when you get this disease?

Characteristics of Life

Living things are organized at different levels.

Organization of living things:-Cell(Smallest)TissueOrganOrgan SystemOrganism(Biggest)

-A cell is the smallest living thing.

History of Cells and Microscopes

-In the 1600’s compound light microscopes were invented. These microscopes use a series of lenses to magnify objects.

-Magnify means to make objects look bigger. -After the invention of the microscope,

scientists began to look at cells under the microscope.

-Robert Hooke used a compound light microscope to look at dead cells from an oak tree. He named what he saw “cells” because they reminded him of the cells the monks lived in.

MicroscopesOriginal Microscope from 1600’s

Compound light microscope used today.

History of Cells and Microscopes

-In the 1930’s electron light microscopes were invented which allowed scientists to look at even smaller objects, such as organelles.

II. Cell Theory-In the 1830’s something called the “Cell Theory” became a

popular way of describing life in terms of cells.

-The cell theory is made up of three main ideas:

1. All organisms are composed of one or more cells. An organism may be made up of one cell, such as bacteria, or may be multicellular, that is have many cells, such as plants and animals.

2. The cell is the basic unit of structure and organization or organisms. Although organisms such as humans, dogs and trees can become very large and complex, the cell remains the simplest, most basic part of an organism.

3. All cells come from preexisting cells. This means that a cell comes from a parent cell (one parent cell divides to become two daughter cells).

Red Blood Cells

III. Types of Cells-There are two types of cells:

1. Prokaryotic cells do not have a nucleus or any other membrane-bound organelles. Ex: Bacteria

Two Types of Cells:

2. Eukaryotic cells do have a nucleus. Ex: Plant and animal cells.

Prokaryote vs. Eukaryote

Prokaryote:

-has no organelles (no nucleus)

Eukaryote:

-has organelles (has a nucleus)

Both:

-are living

-have DNA

-are cells

IV. Parts of the Cell

-Just like our bodies, cells must have different structures which help them live.

-They need their own version of skin, a stomach, blood and a brain to survive.

IV. Parts of the Cell

-Organelles are small membrane-bound structures found inside the cell which have special jobs to help the cell survive.

IV. Part of the Cell

1. The plasma membrane is the boundary between the inside of the cell and the outside of the cell.

IV. Parts of the Cell

The Plasma Membrane is selectively permeable, which means it only lets certain things into and out of the cell. This helps maintain homeostasis inside the cell. Homeostasis is a balance inside the cell.

Selective Permeability

IV. Parts of the Cell-The plasma membrane is a phospholipid

bilayer which means that it is made up of two stacks of lipids attached to phosphates with proteins in between them. Scientists describe the plasma membrane using the fluid mosaic model; this means that the lipids move around a lot which makes the plasma membrane very flexible.

IV. Parts of the Cell2. The nucleus is called the control center

of the cell because it stores DNA which contain directions for making proteins. DNA strands are often stored as chromatin.

3. The nucleolus is found inside the nucleus and is where ribosomes are made.

Nucleolus contains ribosomes

Nucleus contains DNA

Which part of this cell is the nucleus?

Which part of this cell is the nucleus?

Nucleus

IV. Parts of the Cell

4. After ribosomes are made in the nucleolus, they leave the nucleus and attach to the E.R.Once attached to the E.R., ribosomes make proteins.

Ribosomes

IV. Parts of the Cell

5. The Endoplasmic Reticulum or E.R. is a highly-folded organelle where proteins and lipids (fats) are synthesized. Synthesis means to make something.

IV. Parts of the Cell

6. The Golgi Apparatus sorts and packages the proteins and lipids made in the E.R. and sends them around the cell. The Golgi Apparatus is like the post office of the cell!

IV. Parts of the Cell

7. The Mitochondria is called the powerhouse of the cell because it breaks down sugar into energy in the form of ATP.

IV. Parts of the Cell

8. The lysosomes contain digestive enzymes which break down waste. The lysosomes help digest things we no longer need in our cells so that the cell can get rid of these waste products.

IV. Parts of the Cell

9. The cytoskeleton provides support in our cells.

IV. Parts of the Cell

10. The cytosol is the gel-like liquid inside the cell. The cytosol moves around to provide nutrients to the different organelles inside the cell. In this way, the cytoplasm helps circulate materials inside the cell.

Cytoplasm

What organelle is this?

mitochondria

What organelle is this?

golgi

V. Plant vs. Animal Cells

Plant and animal cells do not have exactly the same organelles. Some organelles are found only in plant cells or only in animal cells.

V. Plant vs. Animal Cells Plant Cells

-have chloroplasts and cell walls

-can make their own food through photosynthesis

-have large vacuoles to store water

Animal Cells

-have centrioles used in cell division

-can’t make their own food

Both Plant & Animal Cells

-both have:

Plasma membranes

Mitochondria

Cytoplasm

Nucleus’

Nucleolus’

Golgi

E.R.

DNA

-both are living

VI. Plant Organelles

Vacuole-stores food and water.

Cell Wall-hard structure that protects and gives plant cells shape.

Chloroplast-turn light energy into sugar.