Shallow groove on the surface of the cortex is called sulcus.
Cortex means the outer layer of an inner organ. The outer layer of the cerebrum is called cerebral cortex, where cerebrum occupies the biggest part of the brain. A human being has four lobes of the cerebral cortex which include temporal lobe, parietal lobe, occipital lobe, and frontal lobe.
Cortex has six layers of different types of neurons which are responsible for higher information processing and thinking. Cerebral cortex controls general movement, behavioural reactions, perception and visceral functions. We term the grooved layer as the brain itself.Cerebral cortex consists of large amounts of sulci and gyri(sulcus and gyri in singular). The number of gyri correlates to the processing ability of the animal.A man has big gyri compared to a rat.
Answer:
The process where part of the DNA is saved during replication is known as semi conservative replication.
Explanation:
During cell division, a cell must first replicate its DNA (Deoxyribonucleic acid). When a cell divides into daughter cells , the DNA of the parent cell must be copied because DNA contains the genetic material of an organism. DNA replication is the process in which DNA is copied during the cell division cycle. During replication, the complementary strands of the original double helix DNA are separated and one of the two strands in the original molecule is saved in the new DNA molecule. Thus the new DNA molecule is made of an original strand and a newly synthesized strand. So the DNA replication is known as semi conservative replication. Each strand of the original DNA molecule is referred as the template strand because it provides information for the production of newly synthesized strand. It takes place inside the nucleus
of a cell during the s stage of the cell cycle. During replication, helicase enzyme breaks the hydrogen bonds between the complementary bases (Adenine with Thymine, Cytosine with Guanine) and unwinds the double helix of DNA. The two separated strands create a Y-shaped replication fork and act as templates for the synthesis of new strands of DNA. Enzymes known as DNA polymerases create the new strands.
Explanation:
Cell wall is not present in animal cells .
The Precambrian era envelopes the major bulk of the history of the Earth, beginning from the creation of the planet approx 4.5 billion years ago and terminating with the origination of composite, multicelled forms of life approximately 4 billion years after.
The Precambrian refers to the earliest of the geologic ages that are signified by the distinct layers of sedimentary rock. The Earth was about more than six hundred million years old when life started. The planet had cooled down from its native molten state, creating a solid crust and oceans formed by water vapor in the atmosphere.
At about three billion years ago, the atmosphere of the Earth was virtually devoid of oxygen. At approximately 2.4 billion years ago, oxygen was discharged from the seas as a waste product of photosynthesis by cyanobacteria. The levels of the gas slowly raised, attaining about 1 percent around two billion years ago.
Approximately 800 million years ago, the levels of oxygen attained about 21 percent and started to breathe life into more composite species. The oxygen-rich ozone layer was also created, protecting the surface of the Earth from the harmful solar radiation.
