Cell Structure and Theory

Before scientist could develop cells, they needed

microscopes

What is a theory?

an explanation based on evidence

Is a theory permanent?

No, theories can change with new information

The Original Cell Theory:

1. All living things are made of cells

2. All cells come from pre-existing

3. Cells are the basic unit of structure and organization in living things

Over time scientists learned and added more to the cell theory:

1. Metabolism occurs within cells

2. DNA is passed from one cell to another

3. All cells have the same basic composition

Metabolism:

all interactions among molecules within the well-ordered environment of the cell

What are two examples of metabolism?

photosynthesis and cellular respiration

What is a law?

Predicts the results of what will happen in very specific situations

What is a theory?

Explains why something happens

What is a hypothesis?

Prediction about what you will find in an experiment. Not yet based on data

Prokaryotes

Pro - before

Eukaryotes

Eu - true

Karya

nucleus

Elements of Prokaryotes:

1. Smaller

2. Simple

3. Evolved first - 3.7 billion years ago

4. Floating in cell

5. Lack membrane-bound organelles

Elements of Eukaryotes:

1. Larger

2. Complex

3. Evolved later: 2.7 billion years ago

4. Inside nucleus

5. Membrane-bound organelles

Prokaryotes and Eukaryotes: Structures in Common

1. Cell membrane

2. DNA

3. Ribosomes

4. Cytoplasm

Kingdoms for Prokaryotes:

1. Archaea

2. Eubacteria

Kingdoms for Eukaryotes:

1. Plantae

2. Animalia

3. Fungi

4. Protista

What is the cell membrane?

controls what goes in and out of the cell

What is the Endoplasmic Recticulim?

a network that manufactures and transports chemical compounds

What are Ribosomes?

synthesizes (makes) proteins

What is the Golgi Apparatus?

collects and packages proteins

What is the Lysosome?

contains enzymes that helps digest materials

What is the Vacuole?

stores water, salts, carbs, and proteins

What is the Mitochondria?

The '“powerhouse” of the cell that converts nutrients into energy

What is the Nucleus?

contains the cell’s DNA

Two things not found in an animal cell but plant cell are:

vacuoles and chloroplast

How does the shape of a plant cell differ from that of an animal cell?

An animal cell is circular and plant cells are square shape

What is the function of the chloroplasts?

site of photosynthesis; converts light energy into chemical energy

What is the function of the vacuoles?

helps maintain water balance

Nuclear Membrane: Surrounds the nucleus; controls what goes in/out

Rough Endoplasmic Reticulum (Rough ER)

has ribosomes that help produce proteins for export packaged in vesicles to send to the Golgi

Smooth Endoplasmic Reticulum (Smooth ER)

Lacks ribosomes. Detoxifies harmful chemicals. Produces lipids and sends them to the Golgi

Golgi:

Packages and distributes cell products.

What are the levels of organization in living things?

1. cell

2. tissue

3. organ

4. organ system

5. organism

Population is

a group of organisms of the same species that interbred and live in the same place and time

Key evolutionary stages:

Start: Protocells

1. Multicellular Life

2. Animals

3. Fish and Tetrapods

4. Mammals

5. Great Apes

End: Homo sapiens

Structure:

The shape and parts

Function:

Job/Role

Red blood cells:

Structure: contains hemoglobin/round and smooth
Function: carry oxygen easily to move through the blood vessels

Nerve cells (neurons)

Structure: land and branched
Function: send messages through the body to and from the brain

Skin cells:

Structure: flat and tightly packed together
Function: protect the body/controls what can move in and out

Paramecia:

Structure: covered with cilia/shaped like a torpedo
Function: swims easily

Muscle cells:

Structure: long end elastic
Function: contract and elongate to allow movement