Chapter 7/8 Flashcards
What are organisms?
Living things
What 6 characteristics do organisms exhibit?
- Made of cells
- Need food + energy
- Reproduce
- Produce waste
- Grow
- Respond and adapt
What is Abiogenesis
Life forms essentially spawning from non-living things
What is Redi’s experiment?
He wanted to test if spontaneus generation was real, so he set up a piece of meat to test if it would spawn maggots if the container it was in was closed. It proved spontaneous generation to be false
How were cells first discovered?
They were first discovered in the 1600’s from people observing cork cells under archaic microscopes
Who discovered single-celled organisms?
Anton Van Leeuwenhoek was the first to discover/record them through looking at the plaque on his teeth
Who first discovered that plants had cells?
Schleiden and Schwann both concluded that plants had cells. They also concluded that where nuclei were, there were cells
Cell theory:
- All organisms are composed of one or more cells
- Cells are the smallest unit of life
- Cells are produced from other cells
What were the earliest kinds of microscopes created?
Light microscopes
What are electron microscopes?
They shoot a beam of electrons to scan an object and send an image to the computer its connected to
What is DNA?
It is a long molecule with sections on it called genes. It is in all your cells
What is DNA made of?
Millions of sub-units called Adenine, Cytosine, Guanine, and Thymine. The order of these bases is different for every gene
Describe a Cell Membrane
A protective barrier around the cell. Keeps the cytoplasm contained. Can form vesicles to get things into the heart of the cell
Describe a Nucleus
The nucleus directs all of the cell’s activities. Sends out messenger molecules attached to ribosomes
Describe a Lysosome
They are vesicles that contain digestive enzymes that protect your cell
Describe Endoplasmic Reticulum
It is a maze of folded networks that branch from the nucleus. It is used for materials to be transported through the cell. There is a rough endoplasmic reticulum and a smooth one. The smooth one produces lipids and the rough one has ribosomes
Describe the Golgi Apparatus
Flat shaped discs that replace/modify molecules sent from the Endoplasmic Reticulum. The golgi apparatus is pinched off into vesicles that are then transported to the needed places
Describe the Mitochondria
The mitochondria produces energy needed by the cell. Where glucose is turned into ATP
Describe Centrioles
Cylinders located outside of the nucleus. They help divide cells and direct seperation (plants usually don’t have them)
Describe Vacuoles
Vesicles that hold water, food, etc. Plants usually only have one, and animal cells have small ones
Describe the Cell Wall
Protects and holds the shape of plant cells. Made of cellulose
Describe Chloroplasts
Found only in plants. Contains chlorophyll and causes photosynthesis where the suns energy is turned into sugars
What is the Cell Membrane composed of?
Phospholipids and proteins
What part of the phospholipid is hydrophilic/can dissolve?
The head is able to dissolve, the lipid tail is unable to dissolve
What is Brownian Motion?
When particles suspended move randomly
Difference between osmosis and diffusion
Osmosis can only happen in liquid, while diffusion can happen no matter what
Describe Hypotonic solution
When there is a cell inside some water, and there is a higher percentage of water outside than in the cell
Describe Hypertonic solution
When there a higher percentage of water within the cell
What happens within a hypertonic solution?
The cell will shrink due to diffusion/osmosis. The opposite happens within a hypotonic solution
What is Facilitated Diffusion?
The use of transport proteins to take particles from an area of high concentration to an area of low concentration
What is Active Transport?
When a particle must travel against the concentration gradient
What is Endo and Exocytosis?
When the cell membrane forms a pocket to take proteins across. Exocytosis is the opposite
Why must a cell have a good surface area to volume ratio?
Because if the volume is too large compared to the surface area, it will take too long for the molecules to travel where they need to goq
