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Evolutionary tree of life Animation

By: HWC, Views: 1379

An evolutionary tree of life that reflects mainstream thinking about the connections among major lineages (bya = billions of years ago, mya = millions of years ago). By about 3.8 billion years ago, chemical and molecular evolution had produced the first living cells. The first major divergenc...

Energy sources - types

By: HWC, Views: 7902

• The amount of ATP stored in a skeletal muscle cell can only provide muscular activity for two to three seconds. • Muscle cells must be able to generate additional molecules of ATP to continue contracting. • Muscle cells can generate ATP from several processes: • Phosphogen syste...

Steps of glucose catabolism

By: HWC, Views: 7905

• During digestion, complex carbohydrates are hydrolyzed into monosaccharides, primarily glucose. • The catabolism of glucose is the primary source of energy for cellular production of ATP. • The anabolism of glucose is important in regulating blood glucose levels. • Glucose cat...

Origin of organelles Animation

By: HWC, Views: 1354

Possible origins of the nucleus and other organelles. Some prokaryotic cells have infoldings of their plasma membrane. These infoldings may have served as channels from the cytoplasm to the cell surface. These membranous folds may have evolved into the endoplasmic reticulum and the nuclear e...

Transcription - Introns and exons

By: HWC, Views: 4803

In most eukaryotic genes, coding regions (exons) are interrupted by noncoding regions (introns). Exon - RNA sequences in the primary transcript that are found in the mRNA. Intron - RNA sequences between exons that are removed by splicing. During transcription, the entire gene is copied ...