Biology Test 10/9/24 (DONT DELETE) Flashcards
Who was the first to see cells
Hooke
Who was the first to see living cells
Leeuwenhoek
Who discovered that all plants are made of cells
Schleiden
Who discovered that all animals are made of cells
Schwann
Who discovered that cells come from cells
Virchow
What are the three parts of cell theory
- Cells are the units that make up all living things
- Cells are the units which carry on the functions of all living things
- Cells come from preexisting cells
Compare Eukaryotic and Prokaryotic cells
- Similarities
1. They are both cells
2. They both have “non membrane-bound” organelles - Differences
1. Eukaryotic have a nucleaus, Prokaryotic don’t
2. Eukaryotic have “membrane-bound” organelles, Prokaryotic don’t
3. Eukaryotic are generally larger, Prokaryotic are generally smaller
Why do cells need multiple methods of getting materials across the cell membrane
Molecules can be different, such as being big or small and polar or nonpolar, and they can be going with or against the concentration gradient
Describe the fluid mosaic model
The phospholipids form a bilayer with the phosphates surrounding the lipids, in between some of the phosphates are carbohydrates that determine the membrane fluidity, in between some of the phospholipids are peripheral proteins that are only on one side of the membrane or transmembrane proteins that go all the way through the membrane, then there is water on the outsides of the bilayer
What happens to a cell in a hypotonic solution
It swells and may burst
What happens to a cell in a hypertonic solution
It will shrink and shrivel
What happens to a cell in a isotonic solution
Nothing
A triacylglycerol where one fatty acid has been replaced by a phosphate group, they are an important part of the cell membrane
Phospholipid
Water-loving
Hydrophilic
Water-fearing
Hydrophobic
What part of a phospholipid is hydrophilic
The phosphate
What part of a phospholipid is hydrophobic
The lipid
Why do phospholipids form a bilayer
The lipid is hydrophobic and the phosphate is hydrophilic
What are transmembrane proteins
Proteins that go all the way through the cell membrane, they are used in facilitated diffusion and active transport
What are peripheral proteins
Proteins that are only on one side of the cell membrane
What are the functions of membrane proteins
Transportation - allow things to cross the cell membrane, markers - identify the cells to other cells, and receptors - allow specific molecules to bind to the membrane
What is cholesterol
A small lipid molecule, it fits between the phospholipid and determines membrane fluidity
Why is the word “model” used in “fluid mosaic model”
It is an attempt to explain something they can’t observe
What is “selective permeability”
When the cell membrane allows only certain substances to cross the membrane
What is a concentration gradient
A difference in concentration between two areas
What is the basic difference between passive transport and active transport
Passive transport goes with the concentration gradient so it doesn’t require energy from the cell, active transport goes against the concentration gradient so it does require energy from the cell
What is diffusion
When small, non-polar molecules pass through the cell membrane because of the concentration gradient
What kinds of molecules can cross a cell membrane by diffusion
Small, non-polar molecules
How is facilitated diffusion different from regular diffusion
- It is for molecules that can’t do normal diffusion
- It requires a carrier protein
What are carrier proteins
A type of transmembrane proteins
How are transmembrane proteins involved in facilitated diffusion
They carry the molecules across the cell membrane
How is osmosis different from diffusion
- It is the movement of water instead of molecules
- It is in a direction opposite of the concentration gradient
What is a hypotonic solution
A solution with a lower concentration
What is a hypertonic solution
A solution with a higher concentration
What is an isotonic solution
A solution with the same concentration
What is active transport
When the molecules use energy to move across the cell membrane against the concentration gradient
What is the role of membrane proteins in active transport
They move the molecules across the cell membrane
What is bulk transport
When Endocytosis or Exocytosis is used to transport large molecules across the cell membrane
What is endocytosis
When the cell forms a vesicle from the plasma membrane to take in materials
What is exocytosis
Endocytosis but reversed
Why are endocytosis and exocytosis considered opposite processes
Endocytosis gets materials into the cell, exocytosis gets them out of the cell
What is the role of ATP in a cell
It is the energy used for active transport
