Search Results

Cellular slime mold life cycle Animation

By: HWC, Views: 853

Life cycle of Dictyostelium discoideum, a cellular slime mold Animation. Amoeba-like slime mold cells live in the soil, where they feed on bacteria. The free-living cells grow and reproduce by mitosis. When food dwindles, the amoebas stream toward one another in response to a chemical...

Definition of heart rate

By: HWC, Views: 6744

• Heart rate is determined by the rate of depolarizations of the sinoatrial (SA) node. • Cardiac output is directly proportional to heart rate, the greater the heart rate the greater the cardiac output. • Changes in heart rate are associated with exercise, stress or injury. Nervous ...

Olfaction. or the sense of smell

By: HWC, Views: 4000

Do you ever wonder how you can distinguish thousands of different odors? Olfaction. or the sense of smell, is used by all mammals to navigate, find food, and even find mates. We have millions of olfactory receptors for smelling in our nose. These receptor neurons bind water-soluble or volatil...

Primary Active Transport - electrochemical gradient and ion transport / water movement

By: HWC, Views: 6752

Energy derived from ATP changes the shape of a transporter protein which pumps a substance across a plasma membrane against its concentration gradient An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consis...

Evolutionary tree of life Animation

By: HWC, Views: 262

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...

Glycolysis - and oxygen

By: HWC, Views: 6853

The first reactions involve a single 6-carbon glucose sugar undergoing phosphorylation using two ATP molecules and resulting in two 3-carbon compounds. • The rest of this pathway involves an oxidation reduction reaction, forming two reduced coenzymes, and generation of four ATP molecules. ...

Activation Energy - Valence Electrons

By: HWC, Views: 6087

■ Shared electrons in the outermost orbital form bonds. These electrons are called valence electrons. ■ Valence electrons are disrupted and can be rearranged into a new bond. ■ The energy necessary to start a reaction and break bonds is called the activation energy. ■ Reactants have...

SNP Polymorphysim Microarray Chip - How to Test a Person's DNA

By: HWC, Views: 5939

To test a person's DNA, a researcher first needs a source of tissue. Most of the cells in a blood sample are red blood cells, which lack nuclei, but there are also a number of white blood cells, which do contain nuclei and chromosomal DNA. If we could see a particular DNA sequence in these cel...

Methods that regulate pH

By: HWC, Views: 6807

• The blood flow redistributes fluids that have different pH values between body regions. • The regulation of the blood pH is important to maintain homeostasis. • Blood pH is regulated by: • Chemical buffers. • The respiratory system. • The urinary system. • All thes...