Topic 4A:DNA,RNA and Protein Synthesis Flashcards
What is DNA (deoxyribonucleic acid)?
DNA is a molecule that carries genetic information, consisting of two strands that form a double helix. It contains instructions for protein synthesis.
What are genes?
A gene is a sequence of DNA that codes for a specific protein or function.
How are genes related to chromosomes?
Genes are segments of DNA located on chromosomes. Each chromosome contains many genes, and chromosomes are found in the nucleus of eukaryotic cells.
What is a chromosome?
A chromosome is a long thread of DNA coiled around proteins (histones) that carries genetic information in the form of genes. Humans have 23 pairs of chromosomes.
What is the structure of DNA?
DNA is made up of two long strands of nucleotides, twisted into a double helix. Each nucleotide consists of a sugar, phosphate group, and nitrogenous base (adenine, thymine, cytosine, guanine).
What is the relationship between DNA, genes, and proteins?
DNA contains genes, and these genes provide the instructions for making proteins. Proteins carry out the functions encoded by genes.
What is the role of RNA in protein synthesis?
RNA is involved in carrying the genetic code from DNA to the ribosomes, where protein synthesis occurs.
What are the three types of RNA and their functions?
~mRNA (messenger RNA): Carries the genetic code from the DNA in the nucleus to the ribosomes in the cytoplasm.
~tRNA (transfer RNA): Transfers amino acids to the ribosome to form a protein.
~rRNA (ribosomal RNA): Combines with proteins to form ribosomes, which facilitate protein synthesis.
What is transcription?
Transcription is the process where a segment of DNA is copied into mRNA in the nucleus, which then carries the code to the ribosome.
What is translation?
Translation is the process where the mRNA code is used to assemble amino acids into a polypeptide chain at the ribosome, forming a protein.
How is tRNA involved in translation?
tRNA molecules bring amino acids to the ribosome, where they are added to the growing polypeptide chain according to the mRNA codons.
What are codons?
Codons are sequences of three nucleotides on mRNA that correspond to specific amino acids or signals during protein synthesis.
What is the genetic code?
The genetic code is the set of rules by which information encoded in mRNA is translated into proteins. It is based on codons, each representing an amino acid.
How is the genetic code universal?
The genetic code is the same in almost all organisms, meaning that the same codons specify the same amino acids in different species.
What is the start codon?
The start codon is the first codon in an mRNA sequence (usually AUG), which signals the beginning of protein synthesis.
What are stop codons?
Stop codons (UAA, UAG, UGA) signal the end of protein synthesis, instructing the ribosome to release the completed protein.
What is the difference between DNA and RNA?
~DNA is double-stranded, uses deoxyribose sugar, and contains thymine as a base.
~RNA is single-stranded, uses ribose sugar, and contains uracil instead of thymine.
What is the structure of nucleotides in DNA and RNA?
Nucleotides are made up of a phosphate group, a sugar (ribose or deoxyribose), and a nitrogenous base (adenine, guanine, cytosine, thymine for DNA, and uracil for RNA).
How are the bases in DNA pair?
The bases in DNA pair as follows:
~Adenine (A) pairs with Thymine (T)
~Cytosine (C) pairs with Guanine (G)
How do the bases in RNA pair?
In RNA, adenine (A) pairs with uracil (U), and cytosine (C) pairs with guanine (G).
What is Genetic Code?
The set of rules by which the information in mRNA is translated into proteins, using codons to specify amino acids.
What is a nucleotide?
The basic unit of DNA and RNA, consisting of a sugar, phosphate group, and nitrogenous base.
What is DNA Replication?
The process by which DNA makes a copy of itself before cell division, ensuring genetic information is passed on to daughter cells.
What is RNA?
A single-stranded nucleic acid that plays a crucial role in protein synthesis.
What is a base-pairing?
The specific pairing of bases in DNA and RNA: adenine with thymine (or uracil in RNA), and cytosine with guanine
