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
Which phase is this?
- duplicated chromosomes condense and become visible under the microscopep
- Nuclear membrane (enveloppe) disintegrates
- Spindle microtubules begin to form
Prophase
Which phase is this?
- Spindle apparatus is completely formed
- Spindle microtubles are attached to the centromere regions of the duplicated chromosomes
- Duplicated chromosomes line up at mid-point of the spindle
Metaphase
What phase is this?
- Centromeres of each duplicated chromosome seperate
- Single chromosomes are pulled by their centromeres to opposite poles
Anaphase
Which phase is this?
- Single chromosomes arrive at poles and begin to uncoil
- Nuclear membrane begins to form around each group of chromosomes
- Cytokinesis begins (cell plate forms between the two nuclei and grows outward until it forms a complete cell wall that seperates the two daughter cells)
Telophase in a plant
Which phase is this?
- Single chromosomes arrive at poles and begin to uncoil
- Nuclear membrane begins to form around each group of chromosomes
- Cytokinesis begins (cleavage furrow forms between the two nuclei and pinches the cell into two seperate daughter cells)
Telophase in an animal cell
How do each of these cells divide?
1) Prokaryotic cell
2) Plant cell
3) Animal cell
1) Prokaryotic cell - Binary fission
2) Plant cell - Cell plate formation
3) Animal cell - Cleavage furrow
In a duplicated chromosome, how many Centromeres, Chromosomes, or Chromatides are there?
2 Centromeres
1 Chromosome
2 Chromatides
When viewing the Allium (onion) root tip, which part did we look at?
Was the cell stained?
We were looking at the root apical meristem (region of rapidly dividing cells- near the bottom)
Yes the cell was stained
What is the blastodisc stage?
When a fertilized fish egg that has undergone many divisions to produce a multicellular embryonic stage
*Whitefish Blastodisc - stained black*
Define a colony
It is composed of individual cells or organisms that adhere to each other and may communicate with each other.
Define Multicellular organisms
They are single organisms that have specialized cells that perform different functions
*The differentiation of the specialized cells occurs during the initial development of the organism and is not normally reversible*
What type of cells are these?
1) Chlamydomonas
2) Gonium
3) Eudorina
4) Volvox
1) Chlamydomonas - unicellular
2) Gonium - Colonial
3) Eudorina - Colonial
4) Volvox - Multicellular
Chlamydomonas:
What does the red eyespot do?
It orients the alga towards the light
*sm o size*
Chlamydomonas:
Define the pyrenoid
It is contained within the chloroplast and is responsible for the synthesis of starch from the sugars produced by photosynthesis
*bigger O then the eyespot*
What is the structure of the Chlamydomonas?
It has 2 flagellum, an eyespot, a pyrenoid, and cup shaped chloroplast
Gonium:
What is the small colony group of cells held together by?
The gelatinous matrix
What is the structure of a Gonium?
How many cells?
Has a cup-shaped chloroplast
An eyespot
A pyrenoid
Gelatinous matrix
2-8 cells
How do adjacent cells communicate with each other?
Why is it essential?
Via cytoplasmic bridges
*It is essential for coordination of flagellar movement which propels te colony towards the light*
What is the structure of a Eudorina?
Made up of how many cells?
Gelatinous matrix
Communicates via cytoplasmic bridges
8-32 cells
What is the structure of a Volvox?
Cells
Gelatinous matrix
Cytoplasmic bridges
Daughter organisms (sm green spheres)
What are the 2 types of Volvox cells?
Describe them
(which are formed during the early development of the organism)
Somatic cells - make up the wall of the organism
Reproductive cells - undergo repeated cell division to produce the sm spheres your observed within the larger parent organism
What happens to the parent organism once its mature?
It will rupture and release the sm sperical daughter organisms
T or F:
Uncellular –> Colonial –> Multicellular
True
Which type of reproducing organisms are able to reproduce quicker?
Sexually reproducing organisms are able to evolve more raapidly to adapt to a changing environment
Define Meiosis
A type of nuclear division involved in gamete (egg and sperm) production in animals, and spore production in plants
Define Ploidy
The number number of ‘sets’ of chromosomes found in a cell
Define Diploid
Organisms which have two identical sets of chromosomes in their cell
*Eukaryotic cell = for every chromosome in the nucleus of the cell, there is another chromosome of the same size, shape, and carrying the same gene*
2n = # of chromosomes(2x23 = 46 chromosomes)
Define homologous chromosomes
Similar looking chromosomes
Define haploid
If there is only one of each type of chromosome in the nucleus
n= # of chromosomes
(humans = 23 chromomes)
The particular form in which a gene exist (termed an ____) is either ________(represented by____________) or _______(represented by __________)
The particular form in which a gene exist (termed an allele) is either Dominant(represented by a capital letter) or recessive (represented by a lower case letter)
Aa, AA, AaBb are all examples of what?
The genotype;
Simply an ordered list of the alleles
What happens during Meiosis I?
IT halves the number of chromosomes
Diploid –> Haploid
Which phase does this happen during?
- diploid cell
- Duplicated chromosomes condense
- nuclear membrane disintegrates
- spindle microtubles begin to form
- Homologous chromosomes move toward each other to form bivalents
- Genetic exchange occurs between homologous chromosomes during a process called crossing over
Prophase I
of Meiosis I
Which phase does this happen during?
- Spindle microtubules attach to the centromeres of each duplicated chromosome
- bivalents line up along the midregion (equatorial plate) of the cell
Metaphase I
of Meiosis I
Which phase does this happen during?
- The homologous chromosones seperate from each other and are moved to opposite poles of the cell by the spindle apparatus
Prophase I
of Meiosis I
Which phase does this happen during?
- Duplicated chromosomes arrive at poles and begin to uncoil
- spindle apparatus disappears
- nuclear membranes start to form
- Cytokinesis I is completed
- At the end of this stage, each daughter cell contains the haploid # of duplicated chromosomes (n=2)
Telophase I
of Meiosis I
What happens during Meiosis II?
Seperates duplicated (haploid) chromosomes into single chromosomes
What phase does this happen during?
- Duplicated chromosomes condense again
- Nuclear membranes disintegrate again
- New spindle apparatus forms
Prophase II
of Meiosis II
What phase does this happen during?
- Spindle microtubules attach to the centromeres of each duplicated chromosome
- Duplicated chromosomes line up individually allong the equatorial plate of each of the daughter cells
Metaphase II of Meiosis II
What phase does this happen during?
- Centromeres of each duplicated chromosome seperate and the resulting single chromosomes are moved to opposite poles by the spindle apparatus
Anaphase II of Meiosis II
What phase does this happen during?
- Single chromosomes arrive at opposite poles and start to uncoil
- Spindles disappear
- nuclear membranes will reform
- nucleoli will become visible
- cytokinesis II is completed
- there will be 4 daughter cells, each containing the haploid number of single chromosomes (n=2)
Telophase II of Meiosis II
In plants, meiosis occurs in diploid cells called _____ within reproductive organs called ______ to form haploid ______
In plants, meiosis occurs in diploid cells called sporocytes within reproductive organs called sporangia to form haploid spores
In a chive flower (Allium tuberosum) what is the type of stain used?
Aceto-orcein stain
Plants have a complex life cycle called ______
Alternation of generations
*meaning they have distinct multicellular haploid and diploid stages*
Alternation of generations:
The haploid generation produces ______ and is therefore called the ________
The diploid generation produces _____ and is called the _________
The haploid generation produces gametes and is therefore called the gametophyte
The diploid generation produces spores and is called the sporophyte
In plants, meiosis occurs in diploid cells within structures called _____ in the sporophyte plant, and results in the production of haploid ________
In plants, meiosis occurs in diploid cells within structures called sporangia in the sporophyte plant, and results in the production of haploid spores
Fern plant:
The leaves grow out from a horizontal underground stem called ______ which bears many roots. The brown spots called _____ develop on the undersides of mature leaves
The leaves grow out from a horizontal underground stem called rhizome which bears many roots. The brown spots called sori develop on the undersides of mature leaves
When the ____ are mature, they are discharged from the _____
When the spores are mature, they are discharged from the sporangia
Inside each sporangium, diploid cells called ______ undergo meiosis to form haploid cells called spores
Sporocytes
The fern is a sm heart shaped plant called ______ that develops fine, root like structures called ____
Prothallus
Rhizoids
How does the gametophyte obtain food (sugar)?
Spores
How does the fern gametophyte obtain water from the soil?
Stalk
What is the difference between antheridia and archegonia?
Antheridia = male- gives rise to flagellate sperm cells
Archegonia = female - only a single egg cell is developped
_______ emerges from a gametophyte
Sporophyte
In animals, meiosis occurs in diploid cells in reproductive organs called ____ or _____
This nuclear division results in the production of ________
Ovaries (female)
Testes (males)
Haploid gametes (eggs or sperm)
What 2 events occur in Prophase I of meiosis that do NOT occur in Prophase of mitosis
Prophase I:
- Homologous chromosomes move toward each other to form bivalents
- Genetic exchange occurs betwwen homologous chromosomes during a process called crossing over
How do the products of mitosis in one diploid cell differ from the products of meiosis in one diploid cell?
Mitosis = 2N = diploid = each cell has 2N
Meiosis = N=2 = 4 cells = each 1N
