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Lenz/Marra: Biology Senior Semester 2 Final

Terms in this set (40)

Osmosis
Diffusion of water through a selectively permeable membrane
Diffusion
The process by which molecules move from an area of higher concentration to an area of lower concentration.
How are osmosis and diffusion similar?
-both processes require no energy
-they both play important roles in the human body
How are osmosis and diffusion different?
-diffusion follows a downhill concentration gradient
-osmosis follows an uphill concentration gradient
-osmosis must have a semipermeable membrane
-diffusion will take place with or without a semipermeable membrane
-osmosis depends on particle concentration
-diffusion across a membrane depends on size and electric charge of molecule
What passage regulates the movement of water/other substances into cell?
Semipermeable membrane
Hypertonic
Having a higher concentration of solute than another solution
Hypotonic
Having a lower concentration of solute than another solution
Isotonic
When the concentration of two solutions is the same
Plant cell during osmosis
-If a plant cell is placed in a hypotonic solution, it will take up water and start to well, but it will not burst because of the cell wall. The cell will become hard and turgid.
-If the plant is placed in a hypertonic solution, it will shrink and crumple in a process called plasmolysis.
Animal cell in osmosis
-If an animal cell is placed in a hypotonic solution, it will fill up with water and burst, in a process called lysis.
-If an animal cell is placed in a hypertonic solution.
Mitosis
A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.
-Mitosis is the part of the cell division process in which the DNA of the cell's nucleus is split into two equal sets of chromosomes
Cell Cycle of Mitosis
Before: interphase (G1,S,G2)
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
(Cytokinesis begins in anaphase but finishes in telophase)
Abbreviation: PMAT
Prophase
-First, the chromatin, a loose complex of DNA and protein molecules in the nucleus, becomes more condensed.
-Second, the nuclear membrane breaks down, no longer forming a barrier around the nucleus
-The two microtubule organizing centers, which were positioned near the nucleus, begin moving apart
-The microtubules make contact with chromosomes, the point of contact becoming a structure called the kinetochore, one on each sister chromatid. The extensive structure of microtubules make up a mitotic spindle, which will eventually pull the sister chromatid apart.
Metaphase
-Spindle fibers that are attached to the chromosomes move them towards the microtubule organizing centers, in this sort of tug-of-war battle.
-The Battle make the chromosomes line up on a plate at equidistance from the microtubule organizing centers, called the metaphase plate.
-After they are aligned, however, anaphase begins.
Anaphase
-Until anaphase, the sister chromatids remain tightly paired, thanks to the protein called cohesin, which hold the DNA and colecules together along their length.
-At the beginning of anaphase, cohesin breaks down, and the sister chromatids separate.
-The now chromosomes are pulled to opposite ends of the cell, and this movement is responsible for the v-shape in the chromosomes.
-In animal cells, the kinetochore lengthen and the animal cell lengthen into more of an oval shape. Due to the cell walls of plant cells, the cells maintain their shape.
Telophase
-As the cells approach the opposite ends of the cells, the process of prophase happens in reverse.
-The microtubules are no longer needed, and they begin to disintegrate.
-Bits of disintegrated membrane materials from a nuclear membrane around each chromosome
-The chromosomes themselves, now a singular DNA molecule, becomes less condensed
Cytokinesis
-In animal cells, a ring of microfilaments contract the center of the cell, pinching the cell roughly in half
-Plants create a cell plate that divides the cell in half
Meiosis
A cell division that produces four daughter cells each with half the number of chromosomes from the parent cell. These daughter cells are gametes, or the sex cells, that play a major part in reproduction.
Somatic cells
Any cell of a living organism other than the reproductive organism
Gametes
Sex cells, or sperm and egg/ova
Diploid
Containing two complete sets of chromosomes, one from each parent
Haploid
An organism or cell having only one complete set of chromosomes
Homologous pair
A pair of chromosomes, one from each parent, that have relatively similar structures and gene values.
Stages of meiosis 1
1. Metaphase I
2. Anaphase I
3. Telophase I and cytokinesis
MAT
Stages of meiosis 2
1. Prophase II
2. Metaphase II
3. Anaphase II
4. Telophase II and cytokinesis
PMAT
Prophase I
-During this phase, the chromosomes condense, the nuclear membrane dissolves, and the spindle fibers begins to expand
-A key difference from mitosis is that in prophase I of meiosis, synapsis occurs: the homologous chromosomes find each other and line up close together, so that the four chromatids form a structure called a tetrad
Metaphase I
-The pair of homologous chromosomes are positioned midway between the two microtubule organizing centers (homologous chromosomes does not occur during mitosis)
-spindle fibers are attached at the centromere at each homologous chromosomes
Anaphase I
-The homologous chromosomes separate as they are dragged to opposite ends of the cell
-Sister chromatids do not separate, as they would have in mitosis
Telophase I
-nuclear membranes from around the separated chromosomes.
-Each daughter nucleus contains half the number of chromosomes that were originally present, so they are haploid.
-Cytokinesis divides the daughter cells
Prophase II
-chromosomes condense, the nuclear membrane (if present) dissolves, and the spindle fibers begin to form
Metaphase II
-the spindle fibers attached to the sister chromatids move the chromosomes to the center of the cell
Anaphase II
-sister chromatids separate and are moved to opposite ends of the cell
-new nuclear membranes form around the chromosomes
Telophase II/cytokinesis
-total of four haploid daughter cells, each containing one chromatid from each homologous chromosome pair in the original parent cell
What are the three sources of genetic recombinant/variability?
...
Karyotype
A display of the chromosome pairs of a cell arranged by size and shape. It can detect gender (as indicated by the X and Y chromosomes), and the karyotype indicates any genetic disorder that one may have.
Nondisjunction
The failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei
Which chromosomes determine the sex of the baby?
The XY-chromosome or the XX-chromosome
What is the SRY gene?
The SRY gene is found on the Y chromosome. The sex-determining region Y protein produced from this gene acts as a transcription factor, which means it attaches (binds) to specific regions of DNA and helps control the activity of particular genes. This protein starts processes that cause a fetus to develop male gonads (testes) and prevent the development of female reproductive structures (uterus and fallopian tubes)
Gregor Mendel
Augustinian monk and botanist whose experiments in breeding garden peas led to his eventual recognition as founder of the science of genetics (1822-1884)
-important to remember that he did not discover codominance or incomplete dominance
CRISPR
Clustered Regularly Interspaced Short Palindromic Repeats. Used to edit base pairs of genes
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