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Results for: 'single pore'

What are the Parts of a Plant Cell?

By: HWC, Views: 6775

Every chloroplast in a plant cell is packed with stacks of flattened sacs called thylakoids. The thylakoid membranes contain chlorophyll, as well as most of the other components required for the light reactions of photosynthesis. The chlorophyll-containing structures within the membranes are c...

Sperm Formation

By: HWC, Views: 5722

Spermatogenesis takes place inside the seminiferous tubules. Diploid spermatogonia located near the outer edge of the tubule divide mitotically to form primary spermatocytes. The first meiotic division produces secondary spermatocytes with a haploid number of duplicated chromosomes. T...

DNA Sequences - Dideoxy Sequencing

By: HWC, Views: 7044

A short, radiolabeled primer is annealed to the single-stranded DNA to be sequenced. The DNA serves as a template for in vitro DNA synthesis. The DNA-primer mixture is split into four separate tubes. DNA polymerase and a solution of dNTPs are added to each tube. One of the four 2',3' dideoxy-N...

Monohybrid crosses

By: HWC, Views: 5582

A monohybrid cross is a cross between two parents that breed true for different versions of a single trait. In this example, that trait is flower color. The allele that specifies purple flowers is dominant over the allele that specifies white flowers. The purple-flowered plant has two domin...

Polymerase chain reaction PCR - Animation

By: HWC, Views: 1598

Polymerase chain reaction (PCR) is a method that amplifies fragments of DNA. The purpose of PCR is to create copies of a specific region of DNA. To use this technique, researchers must know the base sequences at either end of the region of interest. They use this information to create...

Generalized life cycles for plants and animals Animation

By: HWC, Views: 1784

But the life cycles of plants and animals differ in their details. In animals, a multicelled diploid stage gives rise to single-celled haploid gametes, the eggs and sperm. These gametes combine at fertilization to form a diploid zygote, which grows and develops into a new multicelled animal...

New DNA Strand Replication

By: HWC, Views: 7121

First step: strands are separated • Helicase unwinds the DNA double helix at the replication fork • SSBs coat the single strands to prevent reannealing • Polymerase attaches nucleotide at 3' end • Synthesis is in 5' to 3' direction DNA Polymerase: • Only extends nucleic ac...

Status Epilepticus

By: Administrator, Views: 10709

Status epilepticus (SE) is a single epileptic seizure lasting more than five minutes or two or more seizures within a five-minute period without the person returning to normal between them. Previous definitions used a 30-minute time limit. The seizures can be of the tonic–clonic type, with a re...

Hydrogen bonds vs. Ionic bond

By: HWC, Views: 6510

The slight positive charge of a hydrogen atom in a water molecule can attract an atom with a slight negative charge, such as the nitrogen in a molecule of ammonia. This forms a hydrogen bond between the two atoms. Hydrogen bonds join the two strands of a DNA molecule. Although hydrogen bo...

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