Lab 3 & 4 Flashcards
Define: Solute
A substance that is dissolved in a liquid
(solvent)
ex. Sugar
Define: Solvent
A liquid that has dissolved or can dissolve one or more solutes
ex. H2O
Define Solution
A liquid (solvent) and its dissolved solutes
Plasma membranes are selectively permeable; they allow certain kinds of sm molecules to pass through freely by _______ and ______ which are both _________ processes
Plasma membranes are selectively permeable; they allow certain kinds of sm molecules to pass through freely by diffusion and osmosis which are both passive transport processes
What is Diffusion?
The random movement of molecules of a substance from an area of high concentration of that substance to and area of low concentration of that substance
What is Osmosis?
Osmosis is the movement of a solvent (water) through a selectively permeable membrane from an area of low solute (Hypotonic) concentration to an area of high solute (Hypertonic) concentration
What are isotonic conditions?
When solute concentrations are the same inside and outside of the cell
= equal movement of water in and out of the cell
Define Hypertonic
When the cell has a higher solute concentration than their environment
Define Hypotonic
When the cell has a lower solute concentration than its environment
If the cell is Hypertonic and the environment Hypotonic, which way is the water moving?
The water is moving into the cell by osmosis
If the cell is Hypotonic, and the environment is Hypertonic, which way will the water move?
The water will move out of the cell by osmosis
The cell has an internal solute of 0.9%
It is placed in a salt solution of 3%
Hypotonic? Hypertonic?
Movement in or out of the cell?
Will the cell burst or shrink?
Cell = hypotonic
Solution = hypertonic
The water will move out of the cell by osmosis
The cell will shrink
The cell has an internal solute of 0.9%
It is placed in distilled water
Hypotonic? Hypertonic?
Movement in or out of the cell?
Will the cell burst or shrink?
The cell is Hypertonic
The solution is Hypotonic
The water moves into the cell by osmosis
The cell will burst
The normal environment for a red blood cell is the liquid component of blood called plasma.
Is the cytoplasm of the red blood cell hypertonic, hypotonic or isotonic to the plasma?
Isotonic;
It has the same concentration inside and outside of the cell
Tradescantia
Plant cells have a large central vacuole, where the water is stored. If you water a plant like Tradescantia with tap water, which is a hypotonic solution, water enters the plant’s cells causing the central vacuole to swell. What prevents the plant cells from bursting?
The cell wall
Amoeba
The contractile vacuole, which functions in osmoregulation (control of water balance within the cell). The contractile vacuole removes excess water that continuously flows into the cell. Is the cytoplasm of Amoeba hypotonic or hypertonic to its environment?
Hypertonic
Define Osmoregulation
The control of water balance within the cell.
Removes excess water that continously flows into the cell.
Define tugor pressure
In what type of cells?
In plant cells, the net movement of water into the cell forces the plasma membrane to push it outward
**Prevents from bursting for an elastic but rigid cell wall
- This is where the crispness of leaf tissue and general rigidity of plants comes from
Define Plasmolysis
The cell vacuole decreases in size and the plasma membrane pulls away from the cell wall
What is the difference between the turgid cell aand the plamolysed cell?
The turgid cell - has a central vacuole, cell wall and plasma membrane are attached
Plasmolysed cell - the cell membrane pulled away from the cell wall (you can see the solution)
How do Prokaryotic cells divide?
By binary fission
Describe the cell division process of a Prokaryotic cell
3 steps
1) The cell’s single chromosome, which is in the form of one circular loop of DNA, will replicate
2) The 2 resulting chromosomes then seperate and the plasma membrane and cell wall grow inward to divide the original cell into two identical daughter cells.
3) Plasmids are also duplicated and move into the 2 daughter cells
What is the Escherichia coli bacteria?
Every how often can they duplicate?
It is the bacteria responsibl for intestinal problems (food poisoning)
Can double every 20 mins
What are chromosomes composed of?
And where are they located?
Chromosomes are composed of DNA (deoxyribonucleic acid) and proteins
They are located in the cell, and carry the genetic material
There are many specific nucleotide sequences in the DNA and these discrete units of hereditary information are called _____
Genes
The combination of DNA and associated proteins is called ________
Chromatin
Well before cell divsion in eukaryotes the ___________ duplicate to form _________.
this happens during which stage?
Well before cell divsion in eukaryotes the single-stranded chromosomes duplicate to form double stranded chomosomes
This happens during the S stage
The two identical copies of the DNA structures are called _______________
Sister chromatids
What are the steps of Eukaryotic cell division?
1) Mitosis
2) Cytokinesis
Define Mitosis
It is the division of the nucleus, resulting in the formation of two genetically identical daughter nuclei
*Includes PMAT
Prophase, Metaphase, Anaphase, Telophase
Define Cytokinesis
The division of the cytoplasm between the 2 resulting daughter cells
What are the 3 major functions of mitosis?
1) The production and maintenance of multicellularity
2) Asexual reproduction (no mating or fusion of cells)
- Ex. Volvox
3) Replacement of old and/or damages tissues
What is the longest phase of cell division?
The interphase
G1, S, G2 stages
What happens during the interphase?
The cell grows, synthesizes new organelles and proteins, and replicates its DNA
*this prepares the cell for the next cell division*
What happens during the G1 stage?
Also called Cell Growth stage
New organelles and proteins are synthesized, and the cell membrane increases in size
* a single chromosome*
What happens during the S stage?
Also called the DNA Synthesis
Each single chromome produces an exact copy of itself by DNA replication, forming a duplicated chromosome (each copy is a chromatid)
What happens during the G2 stage?
There is a second period of cell growth
*Now a duplicate chromosome*
What happens by the end of the Prometaphase?
*Between prophase and metaphase*
The spindle apparatus is completely formed and the microtubules are attached to the centomeres