cell biology Flashcards
protein synthesis what is transcription?
in the nucleus, a copy of one strand of the DNA is made and the mRNA leaves the nucleus, not the DNA strand. mRNA is able to carry the genetic code to the ribosome in the cytoplasm to enable protein to be made
protein synthesis what is translation?
where the mRNA is fed through a ribosome and amino acids are bound together to form a polypeptide chain. The polypeptide chain is processed to form a functional protein.
what 2 types of proteins are formed after translation?
Chemical eg hormone or enzyme
structural eg receptor or a channel
what is DNA and what is it a sequence of?
it is a double helix
each strand is a sequence of nucleotides on a sugar-phosphate backbone
what first determines the nucleotide eg adenine?
nucleobase determines the nucleotide
what forms a codon?
a sequence of 3 nucleotides
how are DA strand arranged?
specific nucleobases pair
Adenine and thymine or Uracil on rna
Guanine and cytosine
what are transcription factors?
Ligands that control the rate of protein synthesis by switching genes on or off. They bind to a receptor on DNA associated with a specific sequence of codons (or genes)
what does the enzyme RNA polymerase do?
after the transcription factor binds to a receptor, the RNA polymerase binds to start of the sequence. (involves energy from ATP and phosphorylation of the receptor) It unzips the sequence of that codon
then pairs free ribonucleotides found in the nucleus
what is the antisense strand?
there’s a sense strand for DNA, and then there’s a second strand of DNA which is called the antisense strand. The sense strand has the information that would be readable on the RNA, and that the RNA becomes apart from it has uracil instead of thyamine. and that’s called the coding side. The antisense is the non-coding strand, but ironically, when you’re making RNA, the proteins that are involved in making RNA read the antisense strand in order to create a sense strand for the mRNA
what does the mRNA move out of the nucleus through and where does it go for translation?
nuclear pores and enters the rough endoplasmic reticulum within the cytosol and binds to subunit of a ribosome, held in place by the large subunit and fed through ribosome
what happens when mRNA is fed through ribosome?
a sequence of transfer RNA tRNA pair there anticodons to the mRNA codons
what does tRNA do?
specific amino acid attached to end which are bound together by peptide bonds , the tRNA delivers specific amino acid. The bound amino acids form a polypeptide chain which detaches from the ribosome and the whole mRNA has been translated
how are proteins processed after leaving ribosome?
within ER, VESICLES GOLGO APPARATUS the polypeptide chains are processed into proteins by either
joining chains
adding sugars or lipids to make glycoproteins or lipoproteins
folding into structures
sections of certain proteins such as hormones are cleaved from the protein to activate it
proteins stored in vesicles for late use
