CHapter 8 honors Bio: Cell Structure and Function

List the three components of cell theory

All living things are composed of cells

cells are the basic units of function and structure in living

all cells come from pre-existing cells.

Hooke:

Cut cork and use a microscope. The things he observed he called them cells because they looked like monastery cells (1665)

Virchow:

New Cells can be produced by existing cells (1855)

Schwaan

All animals are made of cells (1839)

Leeuwenhoek:

First to observe living microorganisms (1670)

Schleiden:

All plants are made of cells (1838)

Scanning Microscope

Samples are vacuumed, sealed, and viewed 3d

Transmition Microscope

samples need to be cut into slices to be viewed, which means that samples are viewed in 2d

Light microscope

samples can be alive; samples need to be stained or dyed to see them 

What are the two significant parts of the cell?

• Cell membrane

• Cytoplasm 

Describe the steps in synthesizing, packaging, and exporting a protein from a cell

1. The nucleus makes ribosomes 

2. Proteins complete their assembly on ribosomes bound to the rough ER

3. A vesicle carries the newly made protein from the rougher to the Golgi apparatus

4. The vesicle binds to the Golgi apparatus 

5. The Golgi apparatus modifies, sorts, and packages proteins 

6. Vescile is sent to different places carrying the modified protein

Describe the differences between plant and animal cells

• Animal Cells: Circular, have lysosomes and centrioles 

• Plant Cells: Rectangular, have cell walls, chloroplasts and a vacuole

The Lipid bilayer of a cell membrane

• hydrophobic tail

• hydrophilic tail

What are the three characteristics of the cell membrane?

• Semipermeable 

• Made of lipids, proteins, and carbohydrates

• Phospholipid bilayer

What happens during diffusion?

Molecules move from an area of high concentration to an area of low concentration until equilibrium is achieved 

How is passive transport different than active transport?

Passive transport does not require energy; active transport does

List the three types of passive transport

• Diffusion

• Facilitated diffusion

• Osmosis 

Hypotonic:

the solution has a higher solute concentration on the inside of the cell than on the outside

Hypertonic:

the solution has a higher solute concentration on the outside of the cell than on the inside

Isotonic:

equal amount of solute in and out of the cell

major types of active transport

• Protein Pumps

• Endocytosis

• Exocytosis

Protein Pumps:

The protein channel acts as a cell to pump ions and molecules across the cell membrane

Endocytosis:

the membrane forms a pocket that then breaks loose from the outer portion of the cell membrane and forms a vesicle in the cytoplasm

Exocytosis:

the membrane of a vesicle surrounds the material and fuses with the cell membrane. The contents of the vesicle are forced out.

Why can some molecules move across the membrane quickly while others cannot? What substances fall into each category?

• Size and polarity

• Quickly: oxygen, water

• Take time: glucose, sugars, proteins 

Why is the membrane a fluid mosaic?

The lipids in the cell membrane aren’t stuck together; they can move and slide past each other.

Nucleus-

Controls most cell processes and contains almost all the cell's DNA and instructions for making proteins/other important molecules

Nuclear pores-

Regulate the passage of molecules entering and leaving the nucleus

Nuclear envelope-

Double layer membrane that protects DNA, separates the nucleus from the cytoplasm and provides the structural framework of the nucleus.

Chromatin-

found in Nucleoplasm, packages DNA into a unit capable of fitting within the tight space of a nucleus.

Nuclolus-

Produces and assembles the cell's ribosomes and transcribes RNA genes

Ribosomes

are small particles of RNA and protein found throughout the cytoplasm in all cells
they assemble proteins by following coded instructions that come from DNA

Endoplasmic Reticulum-

where lipids are synthesized as well as protein and other material exported from the cell

rough ER.

Newly-made proteins leave these ribosomes and enter the ____ ER where they can be chemically modified
Proteins made in the Rough ER include those that will be released from the cell

Smooth ER

contains enzymes that perform specialized tasks (synthesis of lipids or carbohydrates and detoxification of drugs)
has no ribosomes

Newly assembled proteins are carried from the rough ER to the ..... in what?

Golgi apparatus in vesicles

Vesicles-

Enclosed structures that store and move materials between cell organelles, as well as to and from the cell surface

The Golgi apparatus-

modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum
1. The vesicle binds to the Golgi apparatus.
2. The Golgi apparatus modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum.
3. Vesicles are sent to different places.

Vacuoles-

Are large saclike, membrane-enclosed structures that store materials like water, salts, proteins, and carbohydrates.
The vacuole continually fills with excess water from the cytoplasm and then expels it
In many plant cells, there is one large central vacuole filled with liquid
Plant cells generally have large central vacuoles whose sizes change depending on water availability
Once the plant is watered, the vacuoles refill, and the plant stands upright again
The pressure of the central vacuole increases cells' rigidity, which allows plants to support heavy structures (leaves or flowers)

Lysosomes-

Break down lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell and remove "junk" that can accumulate and clutter the cell.
Small organelles filled with enzymes
In animal cells and a few types of plant cells

Centrioles:

A kind of Microtubule
Located near the nucleus and helps organize cell division
Not found in plant cells.

Chloroplasts-

Capture energy from sunlight and convert it into chemical energy stored in food during photosynthesis
Only in plant cells
Inside the organelle are large stacks of membranes that contain chlorophyll

Mitochondria-

Converts the chemical energy stored in food molecules into compounds that are more convenient for the cell to use
Powerhouse of the cell
Carries out cellular respiration
Cellular respiration converts energy from food into a form cells can use

Cell membrane-

Regulates what enters and leaves the cell and protects and supports the cell.
All cells have a cell membrane
made up of a lipid bilayer which gives it a flexible structure that forms a strong barrier between the cell and its surroundings.

Cell wall-

Supports, shapes, and protects the cell
Most of them have walls have tiny holes (pores) that allow water, oxygen, carbon dioxide, and other substances to pass through easily
Only in plant cells and prokaryotes

why did Hooke name cells, Cells?

they looked like the monks rooms in a monastary called cells

when did scientists discover all living things are made of cells

mid 1800s

Prokaryote

smaller
simpler
unicellular
free floating DNA found in cytoplasm
bacteria
no membarne bound organelles

Eukaryote

larger
complex (organelles)
nucleus
enclosed DNA
animal and plant cells
multicellular

what do Prokaryote and Eukaryotes have in common

cell membrane
carry out the same genral functions
living
DNA