Science but its well... everything...?

• 1665 -- ___________ discovered cells by observing cork and called them “cells”

Robert Hooke

• 1674 – ________________ observed microorganisms in pond water (each cell had a “central part” 

Anton van Leeuwenhoek

• Mid 1800’s – work by ________, _______, & ________ is used to develop the cell theory – all plants and animals made of cells and all cells come from other cells

Schleiden, Schwann, & Virchow

What is the Cell Theory (2 things)

Cells are the basic units of structure and function in all living things, New cells come from existing cells

Prokaryotes

simple cells that DO NOT have a nucleus (archaebacteria & eubacteria)

Eukaryotes

complex cells that have a nucleus and membrane bound organelles (protists, fungi, plants, & animals)

Nucleus

Function: 

1. Directs activities of the cell due to nucleotide sequence

Like making proteins to carry out cell processes.

2.  Houses the DNA (genetic material)

Found in all eukaryotic cells

First identified by botanist Robert Brown

Surrounded by a porous nuclear envelope with nuclear pores

Houses the nucleolus 

Nucleolus

A dense (dark) region inside the nucleus that contains DNA and RNA.

Function: Makes both the protein and RNA portions of ribosomes

Chromatin / Chromosomes

Structure inside the nucleus that contains the DNA

Called chromatin when the cell is not dividing and called chromosomes when the cell is dividing and the chromatin is wrapped around proteins called histones.

Function: Contain and organize DNA to be passed to new cells 

Cytoplasm/Cytosol

Cytoplasm – all material between the cell membrane and the nucleus, including organelles

Cytosol - Jelly-like fluid that surrounds the organelles – 80% water

Function: Solution that allows transportation within the cell & provides an environment for the organelles

Plasma (Cell) Membrane

Phospholipid bilayer with embedded proteins and marker glycoproteins 

(glycol – relating to formation of a sugar)

Forms a flexible barrier between the cell and its surroundings

Function: Controls what enters and leaves the cell (Selectively Permeable)

Golgi Apparatus

It consists of six or seven flattened membrane sacs

Discovered by Camillo Golgi

Function: To collect and package proteins and lipids modified in the ER

Cis face

closest to endoplasmic reticulum and receives proteins from the ER

Trans Face

furthest from ER and closer to membrane since many proteins are shipped out of the cell

Mitochondria

It is a double membrane organelle

The inner membrane is folded to increase surface area

Only organelle that contains its own circular DNA and replicates independently

Function: Release energy stored in glucose/oxygen molecules to produce ATP (adenosine triphosphate) during cellular respiration

Endoplasmic Reticulum (ER)

The ER is an extensively folded, internal membrane

Connects to the nuclear membrane

Primary site of protein translation (making protein from RNA)

Function: Assembles, modifies, and transports cellular products (proteins/enzymes/lipids) throughout the cell

Rough ER

Contains ribosomes

Processes the proteins (folds and carries)  made by ribosomes

Smooth ER

Transports compounds around the cell

Processes fats and breaks down toxins in the liver

No ribosomes 

Ribosomes

Small bodies made up of RNA and proteins

Found free in the cytoplasm or attached to the Rough ER

Function: Make proteins  - site of amino acid chain building that then fold to become proteins

Cytoskeleton

Crisscrossed network of proteins fibers

1. Microtubules – hollow tubes of protein 

2. Microfilaments – long, thin protein fibers 

Function: Supports the shape of cells and anchors its organelles

Centrioles

Found only in animal cells

Made of bundled microtubules

Part of the cytoskeleton

Function: Helps organize cell division by orienting the spindle fibers and poles of the cell for cytokinesis 

Vacuole 

Function:

Stores water, sugars, salts and proteins

Provides pressure (turgor pressure) for support in plant cells

Sac-like structures

Usually large in plant cells and smaller and more numerous in animal cells

LYSOSOMES

Lysosomes are spherical organelles in the cytoplasm.

They contain digestive enzymes.

Function: They digest and recycle used components of the cell/ cell invaders

Peroxisomes

Membrane-bound organelle where certain enzymes (such as catalase) are used to break down compounds such as H₂O₂ and detoxify the cell.

Special type of Lysosome

Function: Digests fatty acids & gets rid of the waste product, hydrogen peroxide

Cell Wall

Found in plants, algae, fungi, and bacteria

Surrounds  the plasma membrane

Function: Support & Protection

Chloroplasts

Found only in plants and some algae and protozoans

Contains the green pigment called chlorophyll in thylakoids which are stacked together and called granum

Function:  Helps plants to produce their own food by converting the energy from sunlight into glucose (photosynthesis)

Chromoplasts

Plastids that contain pigments other than chlorophyll

Not found in animal cells

Function: Responsible for flower and fruit color

Cilia

Hair-like structures that are smaller and more numerous than flagella

Not all cells contain these.

Function: Locomotion – moving the entire cell or for moving substances past the cell

Flagella

Long, whip-like structures

Composed of bundled microtubules that project from the cell’s surface

Not all cells contain a flagellum.

Structure of the plasma membrane

The plasma membrane is a double layer of phospholipids

They form a very flexible barrier 

Phospholipid Bilayer

The heads of the molecule are polar (hydrophilic – likes water)

Face outward and form the outside of the plasma membrane

The fatty acid tails are nonpolar (hydrophobic –do not like water)

Face inward and form the middle of the plasma membrane

The heads of the molecule are _____ (hydrophilic – likes water)

Face outward and form the outside of the plasma membrane

polar

The fatty acid tails are ________(hydrophobic –do not like water)

Face inward and form the middle of the 

plasma membrane

non polar

selectively permeable

it only allows certain materials to pass through the membrane

There are proteins embedded in the plasma membrane that serve as:

1. channel proteins

2. marker proteins,

3. receptor proteins

• Channel Proteins-_________________________________

• Like tunnels

serve as passageways to transport substances across the membrane

• Marker Proteins-__________________

  • Kind of like a white flag to immune system cells

identify and distinguish cells

Receptor Proteins- ______________________________________

sends signals to the cell from messenger molecules outside the cell

• Solvent ________________________________

The part of the solution that does the dissolving

Water is the universal solvent

• Solute

  ______________________________________________

The part of the solution that is being dissolved

May be a solid, liquid, or a gas

Passive

• The cell does not use energy to transport substances

  Diffusion

  Osmosis

  Facilitated diffusion

Active

• The cell must use energy to transport substances

  Protein pumps

  Bulk transport

Diffusion

Molecules move from an area of high concentration to an area of low concentration until molecules are evenly dispersed (equilibrium)

Occurs due to Brownian Motion-the constant, random movement of all molecules

Concentration Gradient

The difference in concentration of a substance across a space

The greater the difference the faster diffusion occurs 

Temperature

Higher temperatures make the molecules move faster and speed up diffusion

Facilitated Diffusion

Diffusion of substances through a membrane with the aid of transport proteins

The substance is still moved from high to low concentration so no energy is used (passive transport)

Glucose enters cells through facilitated diffusion

Osmosis

The diffusion of water molecules through a selectively permeable membrane

Low concentration of solution to high!

Isotonic Solution

There is an equal concentration of water inside and outside the cell

Water moves in and out of the cell at equal rates

There is no net change in the cell

Hypotonic Solution

Hypo = below (low)

Lower concentration outside the cell.

The water will move into the cell

The cell will swell and could rupture if it takes in too much water

Hypertonic Solution

Lower concentration inside the cell.

The water will move out of the cell

The plasma membrane will shrivel up 

Hypotonic: Lysis

when an animal cell has ruptured due to water entering the cell

Hypotonic: Turgor Pressure

the expanding of the cell membrane in a plant cell due to water entering the vacuole.

Hypertonic: Crenation

 the shrinking of the cell membrane in an animal cell

Hypertonic: Plasmolysis

the shrinking of the cell membrane in a plant cell

Protein pumps

The substance uses a protein located in the plasma membrane to pass through the membrane

The substance moves from low concentration to high concentration

These pumps transport only a specific type of substance

Bulk Transport

substances are too large to pass through the membrane channels

Endocytosis

• the plasma membrane surrounds the particle and encloses it in a vacuole

  Phagocytosis –endocytosis of solids

  Pinocytosis – endocytosis of liquid

Exocytosis

the reverse of endocytosis

Waste particles that are too large to pass through the membranes are expelled by exocytosis