Protein Synthesis and Cell Division Flashcards
(22 cards)
What organelles are involved in protein synthesis?
Nucleus, ribosomes, rough endoplasmic reticulum (RER), Golgi apparatus, and transport vesicles.
What is the function of the nucleus in protein synthesis?
It contains DNA, which is transcribed into mRNA to begin the process of protein synthesis.
What is transcription?
The process of copying DNA into mRNA in the nucleus.
What is translation?
The process of decoding mRNA into a polypeptide chain at the ribosome.
What happens to proteins after translation?
They are folded in the RER and modified in the Golgi apparatus before transport.
What are the three types of RNA involved in protein synthesis?
Messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
Why is accurate protein folding important?
Misfolded proteins can lead to diseases such as Alzheimer’s, Parkinson’s, and cystic fibrosis.
What are the main stages of the cell cycle?
Interphase (G1, S, G2) and M phase (mitosis and cytokinesis).
What occurs in the G1 phase?
Normal cell functions, growth, duplication of organelles, and protein synthesis.
What happens during the S phase?
DNA replication
Describe the four phases of mitosis?
- Prophase: chromosomes become visible, centriols move to the opposite side of the cell, nuclear envelope disapears, spindle fibres extend and attatch to chromosomes.
- Metaphase: chromosomes align themselves along the metaphase plate, equidistant from the poles.
- Anaphase: Centromere splits, two sister chromatids move to opposite sides of the cell
- Telophase: nuclear enevlope forms, chromosomes change to chromatin, final location of nucleus at opposite ends of the cell.
What is cytokinesis?
The division of the cytoplasm, resulting in two identical daughter cells.
How do cells become specialized?
Through differentiation, where specific genes are activated or repressed.
What is cancer?
Uncontrolled cell division due to mutations in genes that regulate the cell cycle.
What is the difference between a benign and malignant tumor?
Benign tumors are contained, while malignant tumors invade other tissues and can metastasize.
What is apoptosis?
Programmed cell death involving DNA fragmentation (to signal for cell death) and ingestion by phagocytes.
What is necrosis?
Uncontrolled cell death due to injury, leading to inflammation.
What happens to telomeres as a cell ages?
They shorten with each division, eventually leading to the cessation of cell division.
What is a nucleosome and how does it impact cell division?
- The structure of DNA when it is wound around histones.
- non-diving cells are loosluy coiled nucleosomes, forming chromatin.
- dividing cells nucelosomes becomne tightly coiled to form chromosomes.
Describe how a gene is activated or inactivated.
- Activated: loosly wrapped around histones (acetylated) so that histones repel each other and DNA is loose and transcription factors can enter the gene.
- inactive genes are tightly bound to histones so RNA polymerase cannot transcribe the gene
What are the differences between sperm and somatic cells?
- Sperm: sex cells, and divide through meiois
- Somatic cells: non-sex cells and divide through mitosis.
How do cells die overtime?
- Through the ageing process
- As a cell divides it loses sections of the telomere and eventually won’t have telomeres left so it can’t continue dividing.
- Each division results in the loss of a telomere.
