Chapter 8 Cells Flashcards
Used early microscopes to study cork cells. What did he see? What kind of microscope did he use?
He saw cell walls-nothing else.
He was using a compound light microscope with two lenses.
What are the three parts of the cell theory?
Which scientists helped write the theory? There are 3.
All living things are made of cells.
Cells are the units of structure and function of living things.
New cells are produced from existing cells.
Schleiden, Schwann, Virchow
How does a light microscope work to see images? Why are the images larger than the object being viewed?
Light has to pass through the specimen being viewed so specimens need to be thin.
The lenses (two) bend the light and this can cause the image to be larger.
Bending of light is called refraction.
What is the maximum magnification of a light microscope?
1000 X.
The microscopes we use in school have an eyepiece or ocular of 10X. The highest power objective is 100X.
To calculate total magnification, you multiply 10 X 100 = 1000X
What is resolution?
Resolution is the detail that you can see.
I also think of it as how sharp the image is as opposed to blurry.
Electron microscopes have much better resolution than light microscopes due to the much smaller wavelength. Also, light scatters easily-limiting the resolution.
How do electron microscopes work?
There are two kinds: transmission and scanning.
The transmission sends electron beams through the specimen. Scanning scatters electrons across the surface.
Look at the photo attached. Which type of microscope produced this image?
Do you know what the image is showing?
Electron microscopes can see cellular structures that are 1 billionth of a meter in size.
But, there is a downside. What is it?
All specimens have to be put in a vacuum (no air).
So all specimens are dead!
What is a prokaryotic cell?
A prokaryotic cell has no nucleus or other membrane-bound organelles (ex. chloroplast)
What is an example of a prokaryotic organism?
There are three domains of living things. Two include bacteria. One has all of the organisms with eukaryotic cells.
What important role did these organisms play 3 billion years ago?
Created oxygen which changed the atmosphere on earth. (for the better?!)
I guess it depends on who you ask!
What are the four groups of eukaryotic organisms? We call the groups Kingdoms.
“Protists”, Plants, Fungi, Animals
What is an organelle?
a “little organ”
-elle means little or tiny
What are some examples in a cell?
What is the function of the nucleus?
The nucleus contains the information for the cell to function. It is surrounded by a nucleus.
A cell’s information is stored in DNA.
When DNA is wrapped around protein (histones) it is called chromatin.
Tightly wound chromatin is a chromosome.
How many chromosomes do humans have in a skin cell? sperm cell?
What is the function of a ribosome? Which types of cells have ribosomes?
Ribosomes make proteins.
Ribosomes are made in the nucleolus.
All cells-prokaryotes or eukaryotes-have ribosomes.
Even mitochondria and chloroplasts have ribosomes!
What is the function of the rough endoplasmic reticulum?
Synthesize proteins.
What is the function of smooth ER?
No ribosomes!
Synthesis of Lipids and carbohydrates
Detoxification of Drugs
How does the structure of the RER assist its function in the protein-production pathway?
The RER is made of layered sacs. When the attached ribosomes produce proteins the proteins are already within the cavity (lumen) of the ER. The membrane can pinch (see page 250) and make a transport vesicle that can be sent to the Golgi.
All ribosomes start out as free.
But bound ribosomes produce different proteins than free ribosomes.
What kind of proteins are made by ribosomes that bind to the ER?
Bound ribosomes produce proteins that will be exported from the cell.
A good example is insulin. (Where does insulin go?)
What is the function of the golgi apparatus?
The Golgi apparatus receives vesicles (that contain proteins) from the ER.
The Golgi modifies, sorts and packages proteins and other materials from the ER for storage in the cell or release from the cell.
Golgi “tweaks” the proteins-puts finishing touches on them.
From the Golgi, the proteins are put into vesicles and either sent out of the cell or stay inside the cell (in animation, the protein is given to an endosome (immature lysosome).
What is the cell wall?
Strong supporting layer around the cell membrane
Can be found in: plant cells, bacterial cells, fungus and some protists
What is the cell membrane made of?
Why is it selectively permeable?
Composed of phospholipids and proteins
Some substances can pass through them and other materials cannot.
What do we mean by passive transport?
no energy is used.
What is facilitated diffusion?
Molecules move through special protein channels.
No energy is used, so an example of passive transport.
Why is osmosis considered facilitated diffusion?
Water moves through proteins called aquaporins.
What are isotonic solutions?
Same concentration.
Same amount of solute (sugar, salt)
What is a hypertonic solution?
More solute.
What is a hypotonic solution?
less solute
What is osmotic pressure? What can it do to a cell?
The net movement of water out of or into a cell
What is active transport?
The movement of materials against a concentration difference (gradient). This type of transport requires energy.
Think of riding your bike up a hill.
What is molecular transport?
Small molecules and ions are carried across the membrane by pumps. A good example is the sodium-potassium pump.
Take a look at the image. Why is this active transport?
Here is a video: https://www.youtube.com/watch?v=7NY6XdPBhxo
What are the three kinds of bulk transport?
phagocytosis
pinocytosis
exocytosis
