Cells Flashcards
(7 cards)
How is cell differentiation caused?
by changes in gene expression
How are genes expressed?
Genes can be switched on and off. Gene expression results in changes to cell structure and function.
-If a gene is switched on, the protein would be produced.
-If a gene is switched off, the protein encoded by that gene will not be produced
What are stem cells used for?
Before cells specialise, they are called stem cells. Stem cells are used to maintain and repair damaged tissue
How can cells can be genetically identical but function completely differently from each other?
A cell typically expresses only a fraction of its genes, and the different types of cells in multicellular organisms arise because different sets of genes are expressed. Genetically identical cells can differ in structure and function because they have differentiated gene expression.
Protien synthesis- What is transcription?
Takes place in the nucleus, where DNA is used as a template to create messenger RNA (mRNA). RNA polymerase reads the DNA sequence and synthesizes mRNA, which is then processed and transported to the cytoplasm.
Protien synthesis- What is translation?
Occurs in the cytoplasm at the ribosome. The mRNA sequence is read by ribosomes, and transfer RNA (tRNA) molecules bring amino acids that match the mRNA codons. The ribosome assembles these amino acids into a polypeptide chain, which folds into a functional protein.
What types of RNA are involved in protien synthesis and what do they do?
mRNA (Messenger RNA): Carries the genetic code from DNA in the nucleus to the ribosome in the cytoplasm, where it serves as a template for protein synthesis.
tRNA (Transfer RNA): Delivers specific amino acids to the ribosome, where it matches its anticodon with the mRNA codon to ensure the correct amino acid sequence in the protein.
rRNA (Ribosomal RNA): Combines with proteins to form the ribosome, the molecular machine where translation occurs. It helps catalyse the formation of peptide bonds between amino acids.
