Search Results

DNA Replication Factory and Protein

By: HWC, Views: 7878

DNA (deoxyribose nucleic acid) carries all the genetic information needed to re-create itself and to pass on the characteristics of the organism. The “factory” model of DNA replication hypothesizes a specific nuclear structure in which the molecular machinery for replication forks are brou...

New DNA Strand Replication

By: HWC, Views: 7762

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...

The Lagging Strand in DNA Replication and Replication in Action

By: HWC, Views: 7853

The lagging strand is the strand of nascent DNA whose direction of synthesis is opposite to the direction of the growing replication fork. DNA backbones run in opposite directions, the strands in a DNA molecule are oriented antiparallel to one another. New DNA is made by enzymes called DNA...

Cavernous Sinus Larynx Middle Ear Orbit: Granulesm Animation

By: HWC, Views: 7772

The cavernous sinuses are located within the middle cranial fossa, on either side of the sella turcica of the sphenoid bone (which contains the pituitary gland). The cavernous sinuses, a rich plexuses of veins that surround the internal carotid arteries, lie lateral to the pituitary fossa. Ant...

Photosynthesis and Van Helmont Experiment

By: HWC, Views: 7614

All energy on Earth comes from a star, the Sun. Light must travel 160 million kilometers to reach Earth where plants capture this light energy and convert it to chemical energy in the form of sugars. This biochemical process is called PHOTOSYNTHESIS. The summary equation for photosynthesis is ...

Electromagnetic Spectrum, Chlorophyll and Pigment & Light

By: HWC, Views: 8129

The sun gives off radiation that is called the electromagnetic spectrum. This is energy that travels as wavelengths and includes radio waves, X-rays and ultraviolet light. A portion of this radiation is known as visible light, and is the type of radiation that plants use to manufacture sugars. ...

Chloroplast Structure & Light Dependent Reactions (Photosystem 1 and 2 Cyclic Electron Flow)

By: HWC, Views: 7919

The leaf is the principle photosynthetic organ of the plant. This is a cross section of a leaf. The rectangular-shaped cells are part of the photosynthetic tissue called the palisade mesophyll. Each photosynthetic cell can contain several hundred organelles known as chloroplasts. The chlorop...

Calvin cycle (The light-independent reactions )

By: HWC, Views: 8111

The light-independent reactions of photosynthesis occur in the stroma of the chloroplast. Carbon dioxide enters the leaf through tiny pores or stomata and diffuses into the chloroplast. The first stage of the Calvin cycle is the attachment of a carbon dioxide molecule to a 5-carbon ribulose bi...

How does an animal choose what food to eat?

By: HWC, Views: 7795

One might assume that natural selection has influenced the foraging behaviors of animals, and that most animals forage efficiently, spending the least energy to gain the most nutrients. This is the underlying assumption of optimality modeling, a scientific approach to studying foraging behavior. ...