7.3 Flashcards
What is osmosis?
The diffusion of water across a selectively permeable membrane. During this process, water will move across a membrane until the concentration of solute is the same on both sides.
What state are Particles in solids, liquids, and gasses in?
constant random motion.
What is Diffusion?
The net movement of particles from an area of high concentration to an area of lower concentration.
What is dynamic equilibrium?
When diffusion occurs over a long enough time, concentrations will become uniform, and the solution will reach this state. Molecules continue to move, but the overall concentration remains the same.
What is Facilitated diffusion?
It uses transport proteins to move ions and small molecules across the plasma membrane.
What is a process that requires no additional energy?
Passive transport
What are isotonic, hypertonic, and hypotonic solutions?
An isotonic solution has the same concentration of water and solutes as the cytoplasm of the cell. Water still moves through the membrane, but it enters and leaves at the same rate.
A hypotonic solution has a lower concentration of solutes than the cytoplasm of the cell.
The net movement of water is into the cell. As water moves into the cell, pressure increases.
Animal cells can burst when placed in extremely hypotonic solutions.
A hypertonic solution has a higher concentration of solutes than the cytoplasm of the cell.
The net movement of water is out of the cell. As water moves out of the cell, pressure decreases. Hypertonic solutions cause wilting in plants.
How does active transport occur?
With the aid of carrier/transport proteins, often called pumps.
Where are Na+/K+ ATPase pumps found?
In the plasma membrane of animal cells.
What is coupled transport?
A process in which sugars can pair with Na+ ions and enter the cell through a membrane protein called a coupled channel. Allow sugars to enter through facilitated diffusion – saving energy
What is Endocytosis?
The process by which a cell surrounds an object in the outside environment in a portion of the plasma membrane.
What is Exocytosis?
The excretion of materials at the plasma membrane.
What is the diffusion of water across a selectively permeable membrane?
Osmosis
Why is additional energy not required for diffusion?
Because the particles are already in motion.
What is the net movement of particles from an area of high concentration to an area of lower concentration?
Diffusion.
When diffusion occurs over a long enough time, concentrations will become uniform, and the solution will reach this state. Molecules continue to move, but the overall concentration remains the same.
Dynamic equilibrium
What process uses transport proteins to move ions and small molecules across the plasma membrane?
Facilitated diffusion
What are two examples of passive transport?
Diffusion and facilitated diffusion
What is the movement of particles across the cell membrane, against the concentration gradient, and requires energy called?
Active transport.
What is active transport?
The movement of particles across the cell membrane, against the concentration gradient, and requires energy.
What do Na+/K+ ATPase pumps do?
Maintain levels of sodium (Na+) and potassium (K+) inside/outside the cell.
What is a process in which sugars can pair with Na+ ions and enter the cell through a membrane protein?
Coupled transport
What is the process by which a cell surrounds an object in the outside environment in a portion of the plasma membrane?
Endocytosis
What is the excretion of materials at the plasma membrane?
Exocytosis
Who was Robert Hooke?
He was an English scientist who made a simple microscope and looked at the dead cells of oak bark.
What did Robert Hooke Find?
Hooke found small, box-shaped structures and called them cellulae because the boxlike cells of cork reminded him of the cells in which monks live at a monastery.
Who was Anton van Leeuwenhoek?
He was a Dutch scientist who designed his own microscope after he was inspired by a book written by Hooke during the late 1600s.
What did Anton van Leeuwenhoek find?
To his surprise, he saw living organisms in pond water, milk, and various other substances.
What microscope-related event happened in 1665?
1665 Robert Hooke observes cork and names the tiny chambers that he sees cells. He publishes drawings of cells, fleas, and other minute bodies in his book Micrographia.
What microscope-related event happened in 1683?
Dutch biologist Anton van Leeuwenhoek discovers single-celled, animal-like organisms, now called protozoans.
What did Schleiden do?
He determined all plants are composed of cells.
What did Schwann do?
He reported that animal tissues are made up of cells.
What did Virchow do?
He proposed that all cells come from existing cells.
What do compound and electron microscopes have in common?
They both magnify objects.
What is a compound microscope?
A compound microscope is an upright microscope that uses two sets of lenses (a compound lens system) to obtain higher magnification than a stereo microscope.
What are electron microscopes?
An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination.
Optical microscopes do what?
They use visible light and lenses to magnify an object.
Only what microscopes use light and lenses to magnify objects?
Light, compound, or optical.
What do Transmission electron microscopy do?
They aim a beam of electrons at a thin slice of cells using magnets.
What do scanning tunneling electron microscopes do?
They involve bringing the charged tip of a probe extremely close to the specimen so the electrons tunnel through the small gap between the specimen and the tip.
What distinguishes STMs from SEMs and TEMs?
STM can be used with live specimens.
What do scanning electron microscopes do?
They direct electrons over the surface of a specimen.
How do you describe the microtubule configuration of cilia and flagella?
flagella and cilia are composed of 9 pairs of short hairs surrounding 2 single long hairs
What is peptidoglycan?
The substance makes up the prokaryote cell wall.
Made of disaccharides and peptide fragments.
What is the difference between rough and smooth endoplasmic reticulum?
Rough endoplasmic reticulum has ribosomes attached to it.
How are rough and smooth ER found in cells?
Both types are present in plant and animal cells. The two types of ER often appear as if separate, but they are parts of the same organelle.
What is smooth ER?
Smooth endoplasmic reticulum has no ribosomes attached to it and provides a membrane surface where a variety of complex carbohydrates and lipids, including phospholipids, are synthesized.
What is the difference between vacuoles and vesicles?
Other than the fact that vacuoles are somewhat larger than vesicles, the membranes of vesicles can fuse with either the plasma membrane or other membrane systems within the cell.
What is Brownian motion?
Random motion.
What are carrier proteins?
Transport proteins that change shape as particles pass through to help them move through.
