无生源说——从非生命中创造出生命——这是第二个障碍。 The basic building blocks of life aren't unique to Earth: amino acids have been found in comets, complex organic molecules in interstellar dust clouds, water in exoplanetary systems. 构成生命的基本要素并非地球独有:在彗星中发现了氨基酸,在星...
Why are L-amino acids found only in proteins? How spindle fibers are formed in plants? Describe six organelles that are seen in the cells and explain their functions. Which offspring of a single-celled eukaryote would inherit a mutation acquired by the parent cell?
Are amino acids amides? Amides are molecules that contain nitrogen atoms connected to the carbon atom of a carbonyl group. ... It is through this reaction that amino acids (molecules containing both amine and carboxylic acid substituents) link together in a polymer to form proteins....
Where are glucose and amino acids reabsorbed? Where are MHC-II proteins found? Where are MHC-I proteins found? Give examples of a protein. What are the steps for the production of a recombinant protein? Describe the process of protein synthesis. Where does it occur?
Legumes (including soybeans) are especially low in sulfur-containing amino acids. Plant proteins are more likely to cause food allergy and sensitivity than proteins from most animal meats. Five of the top nine food allergens are plant proteins: gluten (a protein found in wheat and related ...
Anticodons are sequences of nucleotides that are complementary to codons. They are found in tRNAs, and allow the tRNAs to bring the correct amino acid in line with an mRNA during protein production. ... It's important thatthe correct amino acids be used in the correctplaces, because amino...
Which of these is NOT correct? a. polysaccharides are made up of monosaccharides. b. triglycerides are made up of fatty acids and glycerol. c. DNA is made up of nucleotides. d. RNA is made up of proteins. e. proteins are made up of amino acids. ...
so hummingbirds meet their needs for protein, amino acids, vitamins, minerals, etc. by preying on insects and spiders, especially when feeding young.Most hummingbirds have bills that are long and straight or nearly so, but in some species the bill shape is adapted for specialized...
What organelles are found in prokaryotes? How are amino acids made in the cytoplasm? Where does the production of messenger RNA take place? Ribosomes are made of A) nucleic acid. B) protein. C) carbohydrate. D) a mixture of protein and nucleic acid. ...
Nitrogen is an essential ingredient for life — an element that is found in proteins, amino acids, and DNA. But not just any nitrogen will do. Most of the time, nitrogen atoms are locked together in close-knit pairs, held together by very strong chemical bonds, which means neither atom ...