Answer: D. It yields chromosomes that contain both maternal and paternal DNA.
Explanation:
The recombination or crossing over is a genetic process. It takes place during the Prophase I of meiosis. The homologous pair align and held together by synapsis. This results in the mixture of genes combination formed from both parents that can be represented as a single chromosome.
If the recombination do not occur then each chromosome will be either 100% maternal or paternal. Thus recombination assures the recombinant chromosomes which consists of genetic material from both parents. Thus the genetic diversity of offspring increases.
Answer:
Wegener thought all the continents were once joined together in an "Urkontinent" before breaking up and drifting to their current positions. But geologists soundly denounced Wegener's theory of continental drift after he published the details in a 1915 book called "The Origin of Continents and Oceans." Part of the opposition was because Wegener didn't have a good model to explain how the continents moved apart.
Explanation:
The smallest type of stream is a brook.
<h2>Mitotic Cell Cycle</h2>
Explanation:
a. Cytochalasin: an inhibitor of actin microfilament
- Cytokinesis is the process by which cytoplasm is divided into two cells hence generation of two daughter cells
- In animal cells the division of cytoplasm starts with the assembly of contractile ring
- Contractile band consists of actin and myosin and catalyze cleavage furrow formation
- Cytochalasin is a drug that blocks the polymerization of actin filament
- When cytochalasin is added dividing cell fails to undergo in cytokinesis due to defective assembly of contractile band
b. Colchicine: an inhibitor of microtubule formation
- Colchicine tightly binds with free tubulin dimer and prevents its polymerization
- In this case mitotic spindle apparatus do not assemble and cells unable to do partitioning of chromosomes into two groups
- Thus cell division is arrested
c. Aphidicolin: an inhibitor of DNA Polymerase activity
- Aphidicolin is used to induce cell cycle arrest via specific inhibition of DNA Polymerase α
- It blocks the cell cycle at early synthesis(S) phase
d. Emetine: an inhibitor of ribosome activity
- It blocks the protein synthesis in eukaryotic cells by binding to small subunit(40 S) of ribosomes
- It interferes with the synthesis and activities of DNA and RNA
Answer:
Genotype: 100% or 4/4 of the progeny will be heterozygous for the trait, Yy.
Explanation:
<u>Available data:</u>
- Two plants differ in the seed color they produce.
- One plant produces green seeds, the other produces yellow seeds.
- Yellow is the dominant phenotype, over green which is the recessive phenotype
- The parental plants are true-breeding
Let us say that the allele Y expresses yellow color and is dominant over the allele y which expresses the green color and in the recessive one.
Cross: a green-seeded plant with a yellow-seeded plant
Parental) YY x yy
Phenotype) Yellow seeds Green seeds
Gametes) Y Y y y
Punnet square) Y Y
y Yy Yy
y Yy Yy
F1) Phenotype: 100% of the progeny will be yellow-seeded
Genotype: 100% or 4/4 of the progeny will be heterozygous for the trait
