Search results for: 'El'

Watch Later 1:29

By: HWC, Views: 2810

Presumed evolutionary branchings in the primate family tree. The first primates arose between 85 and 65 million years ago. The common ancestor of apes and hominids branched off from Old World monkeys about 23 million years ago. The hominid lineage, which includes humans and earlier humanlik...

Watch Later 2:16

Subunits of DNA And Semi Conservative Replication

By: HWC, Views: 3062

Adenine is a purine with a double-ring structure. In double-stranded DNA, adenine base-pairs with thymine. Guanine is a purine with a double-ring structure. In double-stranded DNA, guanine base-pairs with cytosine. Thymine is a pyrimidine with a single-ring structure. In double-stranded DNA, th...

Watch Later 1:34

Cell mediated immune response to a viral infection Animation

By: HWC, Views: 2705

Intracellular pathogens are the targets of cell-mediated immune response. The process begins when a virus infects a macrophage. Another macrophage engulfs the same virus or an antigen from it. In both cells, enzymes cleave the viral antigens into small bits. The fragments move to the cell sur...

Watch Later 2:32

Chromosome structural organization/ Mechanisms for chromosome movement Animation

By: HWC, Views: 2809

How the chromosome is organized. At metaphase, the chromosomes are duplicated and are at their most condensed. In each chromosome, two identical sister chromatids are held together at a constricted region called the centromere. When a chromosome is condensed, interactions among chromosomal ...

Watch Later 0:42

Protein Secondary and Tertiary Structures - Animation

By: HWC, Views: 2871

Amino acid sequence dictates a protein's final shape. The presence of certain amino acids favors a pattern of hydrogen bonding that causes part of the polypeptide chain to coil and twist into an alpha helix. The presence of other amino acids enables hydrogen bonding between strand like r...

Watch Later 4:44

The 4 steps of translation Animation

By: HWC, Views: 2524

Translation is the process of formation of a polypeptide chain according to codon present in mRNA. The four steps of translation are: Activation or charging of tRNA Initiation – recognition of start codon, binding of ribosomal subunits to mRNA and formation of initiation complex with Met-tR...

Watch Later 0:57

Effect of the environment on coat color in the Himalayan rabbit Animation

By: HWC, Views: 2249

An organism's phenotype—the combination of traits that we observe—is the product of interactions between its genotype and the environment. For example. a Himalayan rabbit is completely white at birth. But within weeks, the fur on the rabbits ears, nose, tail. and lower legs darkens. The...

Watch Later 2:02

Transcription—A molecular view

By: HWC, Views: 2230

Transcription, as related to genomics, is the process of making an RNA copy of a gene's DNA sequence. This copy, called messenger RNA (mRNA), carries the gene's protein information encoded in DNA. During transcription, a DNA molecule is copied into RNA molecules that are then used to translate...

Watch Later 0:54

How to make cDNA Animation

By: HWC, Views: 1254

This animation shows how an mRNA transcript can be used to make a cDNA strand.

Search Results