Describe the transcription process that results in synthesis of an RNA molecule. The use of one strand of a DNA molecule as a template. 5. a. Contrast the functions of the three types of RNA molecules. Messenger RNA (mRNA) – copies the coded message from DNA in the nucleus and carries the message to the ribosome.
21. Describe the process of translation. Describe how mRNA translates the message into a protein? How are the amino acids brought to the ribosome? 22.
Codons in mRNA are used to assemble amino acids in the correct sequence to produce a polypeptide chain, which is the process of translation. mRNA binds to the binding site on the smaller ribosomal subunit and tRNA carries amino acids to the ribosome. Cells contain more than twenty types of tRNA, which is more than enough for different amino acids.The codon of mRNA forms hydrogen bonds with the anticodon of tRNA.The tRNA goes back to the cytoplasm to create more amino acids after detching itself from mRNA.Peptide bonds are created between neighboring amino acids, forming a polypeptide chain. rRNA consists of a single polynucleotide strand synthesised in the nucleus. The rRNA form mixes with proteins to form the large and small subunit.
Marshall Nirenberg and Heinrich Matthaei used mRNA made up of repeating uracil nucleotides in a cell free extract. They obtained amino acid chains consisting of phenylalanine. What did they learn when they asked the question, ”What happens when mRNA made up of only cytosine, alanine, and guanine are placed in a cell free extract?” 10. Explain how the structure of tRNA helps it to deliver the correct amino acid to the corresponding mRNA codon at the ribosome. Sketch the structure of a tRNA molecule, making sure to label the amino acid and the
stores proteins and alot of exporting (sending stuff out of the cell) 3. In which part of the cell would you expect to find nucleotides? building block for DNA, DNA found in the nucleus 4. Name the two organelles involved in energy conversion.chloroplast and mitochondria 5. What are the basic functions of the organelles in chapter 4?
Explain the role the hypothalamus and pituitary gland have in the regulation of the endocrine system. What would happen if there were no negative feedback control on growth hormone and thyroid hormone? The hormonal secretion is controlled by negative feedback mechanisms. The stimulus triggers the production of hormone worse direct or indirect effects that reduce the intensity of the stimulus. The simplest case, endocrine activity may be controlled by humoral stimuli – changes in the composition of the exetracelluar fluid.
A receptor organ is a highly specialized part of the body and is selectively sensitive to a definite stimulus. For example, the eyes are sensitive to light waves and the ears to sound waves. The second condition is the presence of a receptor
First a stressor is recognised. Then a signal is sent to the hypothalamus in the brain. This signal triggers the release of adrenaline from the adrenal glands. This
Proprioception sensations provide information about body positions and movement. PERCEPTION: refers to how the brain organizes and interprets sensory information. It can also be defined as an active process in which the brain treats external stimuli as raw material to be shaped, aided by our experience. Gestalt psychologists made a major contribution to the theory of perception by studying the ways people organize and select from the multitude of stimuli that are presented to them. The brain receives information from the environment by way of specialized sensors called receptors.
Describe the relationship between perception and sensation. Explaining clearly why we sometimes experience perceptual illusions. Sensation and perception although closely related, have distinct qualities that set them apart. Sensation is the stimulation of a sensory receptor which produces neural impulses that the brain interprets as a sound, visual image, odour, taste and pain. It occurs when the five sensory organs, thus eyes, ears, nose, tongue and skin absorb energy from a physical stimulus in the environment.