Term
| What do you call a bacterium that can only survive in an oxygen-free environment? (aerobe/facultative anaerobe/obligate anaerobe) |
|
Definition
|
|
Term
| What does the term nitrogen fixation refer to? |
|
Definition
| Converting molecular nitrogen gas into a form useful for life. |
|
|
Term
| Describe how Gram positive bacteria are distinguished from Gram negative bacteria. |
|
Definition
| A purple dye is used to stain the peptidoglycan layer of bacteria. It is then washed away for a short period. Finally, the cells are stained pink. Gram positive bacteria, with their thick peptidoglycan layer, will retain enough of the stain to remain purple. With Gram negative bacteria, their thin peptidoglycan layer means the purple dye will wash away, and you will just see the pink stain. |
|
|
Term
| Name an organelle that is part of the endomembrane system. |
|
Definition
| A lot of possibilities here, but smooth ER, rough ER Golgi, are examples |
|
|
Term
| Through what organelles does a secreted protein follow to get out of a cell? |
|
Definition
| Rough ER, Golgi secretory vesicles, plasma membrane |
|
|
Term
| Endocytosis carried out when the cell protrudes a pseudopodium to surround and engulf a food particle is called (phagocytosis/pinocytosis/receptor-mediated endocytosis). |
|
Definition
|
|
Term
| What is the signal sequence and what role does it play? |
|
Definition
| This is the first amino acids encoded in the translation of a secreted protein. It has a specific sequence that is recognized and causes entire translational complex, including the ribosome, mRNA and the protein being made, to be taken to the ER membrane, and as the protein continues to be made it is passed through the ER membrane, from which it can be transported through the endomembrane system. |
|
|
Term
| Osmosis refers to the movement of what molecule across a semi-permeable membrane? |
|
Definition
|
|
Term
| A transmembrane protein is an example of an (integral/peripheral) membrane protein. |
|
Definition
|
|
Term
| What is a lysosome/what does it do? |
|
Definition
| It is an organelle that produces hydrolytic enzymes. It will fuse with food vacuoles as well as organelles undergoing autophagy in order to recycle the macromolecules for reuse by the cell. |
|
|
Term
| Explain how a difference is salt concentration can lead to hemolysis (the rupturing of blood cells). Use appropriate terms. |
|
Definition
| When a red blood cell is placed in a hypotonic solution, one with a lower salt concentration than that found within the cell, osmosis will lead to a flow of water from low salt concentration to high, and hence into the cell. This will increase the volume within the membrane until it bursts. |
|
|
Term
| Name a component of the cytoskeleton. |
|
Definition
| Microtubules, microfilaments, intermediate filaments. |
|
|
Term
| What protein makes up microtubules? (actin/keratin/tubulin) |
|
Definition
|
|
Term
| What is the function of a gap junction? |
|
Definition
| It links adjacent cells together in a manner that leaves an open passageway through their membranes through which small molecules can pass. This allowing nutrient flow and direct signaling between the cells. |
|
|
Term
| Explain how eukaryotic flagella and cilia are similar, and how they differ. |
|
Definition
| Flagella and cilia have the same basic structure of nine pairs of microtubules around the two. They both extend from a basal body, and are surrounded by membrane. However, flagella are usually much longer and only one or a small number are present in each cell, while there can be thousands of the short cilia. Likewise, they have a different motion, with cilia giving you a beat and recovery stroke, while flagella move in an undulating serpentine fashion. |
|
|
Term
| What is the name for a protein on the cell surface that detects an external signal? |
|
Definition
|
|
Term
| The microtubules that connect to the kinetochore are called (aster/kinetochore/overlapping) microtubules. |
|
Definition
|
|
Term
| What specific process is called mitosis? |
|
Definition
| The division of the nucleus into two nuclei with the full genetic component of the parent cell. |
|
|
Term
| Describe what happens at each step in the cell cycle. |
|
Definition
G1: decision to enter cell cycle, and production of the components necessary to replicate DNA
S: DNA synthesis
G2: production of the other cellular components: proteins, enzymes, membranes, etc.
M: Mitosis and cytokinesis |
|
|
Term
| What does cytokinesis refer to? |
|
Definition
| Separation of cytoplasm and cell membranes subsequent to mitosis. |
|
|
Term
At what stage of mitosis do the chromosomes align at the metaphase plate?
(anaphase/interphase/metaphase/prometaphase/prophase/telophase) |
|
Definition
|
|
Term
| What is the term given to cell division in bacteria? |
|
Definition
|
|
Term
| Contrast cytokinesis in plants to that seen in animals (i.e. explain both in sufficient detail to demonstrate their differences) |
|
Definition
An animal cell carries out cytokinesis by constricting the plasma membrane using actin and myosin. As this constriction becomes progressively tighter, it will pinch off the two cells from each other.
In plants, the presence of the cell wall restricts the ability to constrict the plasma membrane. Instead, plants form a new cell wall by localizing vesicles at the mid-way point that contain the components of the cell plate. As these vesicles fuse, the cell plate grows until it reaches and fuses with the cell plasma membrane to form a new cell wall between the two progeny cells. |
|
|
Term
| When a reproductive cell divides to produce daughter cells with half of the chromosome number as the parent cell, this is called _________________. |
|
Definition
|
|
Term
| At what stage of meiosis do homologous chromosomes separate? (anaphase I/anaphase II/ metaphase I/metaphase II/prophase I/prophase II/telophase I/telophase II) |
|
Definition
|
|
Term
| What is one aspect by which human gamete formation that differs from prototypical meiosis (be specific). |
|
Definition
| There are several: sperm undergo incomplete cytokinesis, eggs suspend the process, and the meiotic plate alignment is off-center, plus they don’t undergo anaphase II until after fertilization. |
|
|
Term
| Describe what chiasmata are, including when they form and the role that they play? |
|
Definition
| Chiasmata are the point where homologous chromosomes cross over. The individual chains are broken and reattached to the equivalent position on the opposite chromosome. This not only provides for genetic recombination, but is critical to forming and maintaining the appropriate alignment and segregation of the homologous chromosomes. |
|
|
Term
|
Definition
| A single copy of a gene, representing one variant at a genic locus that has variation among a population. |
|
|
Term
| When a bacterium acquires free DNA from its environment, this is called (conjugation/ transduction/transformation). |
|
Definition
|
|
Term
| What is meant by Mendel’s Law of Segregation? |
|
Definition
| The individual alleles will separate in different gametes. This also means they are inherited from different parents. |
|
|
Term
| How does an F + cell transfer genetic material to another bacterium. How does this differ from Hfr transfer? |
|
Definition
| It peels off one strand of the F plasmid and passes it in its entirety through a sex pilus to another cell, where the second strand is replicated and the F plasmid formed in the recipient cell, making it F+. In Hfr transfer, the F factor has integrated into the genome, and it begins transferring genomic DNA through a sex pilus to the recipient. There it recombines with the recipient genome. Because of the size of the genome and the instability of the interaction, it cannot transfer the entire genome, and the amount transferred it proportional to the time the two cells interact. The F factor itself is not transferred, so the recipient remains F-. |
|
|
Term
| What is incomplete dominance? |
|
Definition
| This is when the heterozygotes demonstrate an intermediate condition between the two homozygotes, with one copy of the functional allele not able to bring about the full phenotype seen with the homozygote. |
|
|
Term
| If a given breeding has a ¼ chance of producing a green pea and a ½ chance of producing a smooth pea, what are the chances of it producing a smooth green pea? |
|
Definition
| 1/8 (using the multiplication rule) |
|
|
Term
| What is meant by Mendel’s Law of Independent Assortment? |
|
Definition
| This indicates that the alleles for different genes will randomly distribute into gametes, such that there is no greater likelihood that the paternally inherited alleles will remain together in the gametes of the next generation than that they will be separated. |
|
|
Term
| What possible gametes would be produced by an individual with the genotype Aa Bb CC Dd ee? |
|
Definition
| ABCDe, aBCDe, ABCde, aBCde, AbCDe, abCDe, AbCde, abCde |
|
|
Term
| What is a polygenic effect? |
|
Definition
| When a trait is the consequence of multiple genes having an additive effect. |
|
|
Term
| When a single gene affects more than one trait, this is an example of (epistasis, pleiotropy, polygenic effect). |
|
Definition
|
|
Term
| What is meant by mosaicism? |
|
Definition
| Having cells with different genotypes within the same individual. |
|
|
Term
| Describe what is meant by incomplete dominance. Contrast it with both standard Mendelian inheritance, and with co-dominance. |
|
Definition
| Incomplete dominance is when the heterozygotes demonstrate an intermediate condition between the two homozygotes, with one copy of the functional allele not able to bring about the full phenotype seen with the homozydote. This contrasts with standard Mendelian genetics, wherein a single copy of the dominant allele will display the same full phenotype seen in the heterozygotes. With codominance, more than one dominant allele exists, and in the heterozygote you see the full effect of both dominant alleles. |
|
|
Term
| When the pattern of inheritance of a gene is different depending on the sex of the offspring, the gene is said to be ________________? |
|
Definition
|
|
Term
| Why are homozygotes rarely seen for genetic disorders with dominant inheritance? |
|
Definition
| They have severe phenotypes and are usually lethal early in life. |
|
|
Term
| What is an autosomal allele? |
|
Definition
| Autosomal refers to being present in two copies independent of sex, so an autosomal allele would be an allele on the autosomal chromosomes, or in the pseudo-autosomal region of the sex chromosomes. |
|
|
Term
| Explain how meiosis accounts for Mendel’s two laws of genetics. |
|
Definition
During prophase I, homologous chromosomes align and undergo synapsis (they come together, form a connecting protein complex, and undergo crossing over). When in anaphase I, the homologous chromosomes are separated into what will become different daughter cells. This accounts for Mendel’s Law of Segregation.
Mendel’s Law of Independent Assortment arises from two factors. First, during metaphase I, homologous chromosomes align randomly on the metaphase plate, meaning genes that are on different chromosomes will assort randomly. For genes on the same chromosome, the crossing over in prophase I brings about the independent assortment, if they are not too close together. |
|
|
Term
| What is the cause of genes being ‘linked’? |
|
Definition
| This happens when they are physically located on the same chromosome. |
|
|
Term
| When an individual has an extra copy, or one fewer copy, of a single chromosome (i.e. their chromosome number differs by 1 from what is expected for their species) they are said to be: (aneuploidy, haploid, triploidy) |
|
Definition
|
|
Term
| What characteristics of the fruit fly make it a good model system? |
|
Definition
| Small, fast generation times, many offspring, easily observed phenotypic differences. |
|
|
Term
| Explain how the principle of crossing over during meiosis can be used to map genes on a eukaryotic chromosome. |
|
Definition
| Because the likelihood of crossing over is roughly proportional to the distance between the genes, then by looking at a large number of individuals and quantifying the proportion of times a crossover has occurred between the two sites of interest, one can get a feel for their distance on the chromosome. By combining these analyses looking at multiple pairs of genes, one can place them in relative order based on the distances deduced from crossing over. |
|
|
Term
| What is the term for a virus that infects bacteria? |
|
Definition
|
|
Term
| When a virus inserts itself into the genome of a cell and remains dormant rather than progressing to lysis, this is the (lysogenic/lytic) phase. |
|
Definition
|
|
Term
| What is a viral envelope? |
|
Definition
| This is a lipid bilayer surrounding the capsid of some viruses. It arises from the plasma membrane of the cell from which the virus buds, and frequently contains glycopeptides that take part in host-cell recognition. |
|
|
Term
| Give a detailed description of the life cycle of a retrovirus? |
|
Definition
| A retrovirus infects a cell by binding to receptors on the membrane and being drawn into close proximity, so that the envelope fuses with the cell membrane. The capsid enters the cell and the genomic RNA is unpacked. Reverse transcriptase makes a DNA copy that then inserts into the host genome. From there, it is transcribed both to reproduce the viral genome and to serve as an mRNA for the production of the viral proteins. These self-assemble, before the mature virus buds off from the infected cell. |
|
|
Term
| What biomolecule represents the major reservoir for energy in the cell? |
|
Definition
|
|
