Cell Biology Chapter Overview

What effect does a decreased surface area to volume (SA/V) ratio have on a cell's efficiency?

During DNA replication, what role does primase play?

What is the correct order of steps in the transcription process?

What is the role of tRNA in translation?

What is the significance of the stop codon in the translation process?

What does the leading strand do during DNA replication?

Which component of the ribosome plays a critical role in linking amino acids during protein synthesis?

Which phase of the cell cycle is primarily associated with DNA replication?

What initiates the transcription process at the promoter region?

What is the first amino acid added to a growing polypeptide chain during translation?

Surface Area to Volume Ratio (SA/V) and Cell Cycle

A decreasing SA/V ratio in a cell makes nutrient and waste transport less efficient due to lower surface area relative to volume.
A small SA/V ratio in large cells triggers signals for cell division.
Conversely, an increasing SA/V ratio (smaller cells) simplifies nutrient/waste management.

DNA Replication

Primase: An enzyme crucial in DNA replication, adding RNA nucleotides complementary to the DNA template.
Leading Strand: Synthesized continuously from the 5' to 3' direction on the template strand.
Okazaki Fragments: Short DNA segments formed discontinuously on the lagging strand, synthesised from the 5' to 3' direction in separate sections.
Lagging Strand: New DNA synthesized discontinuously in short segments opposite the replication fork.

Translation (RNA to Protein)

tRNA (Transfer RNA): Carries amino acids to ribosomes for protein synthesis.
rRNA (Ribosomal RNA): Forms ribosomes, aiding in protein synthesis and amino acid linking.
mRNA (Messenger RNA): Carries the genetic code from DNA to ribosomes for protein synthesis.
Methionine: The initial amino acid in protein synthesis.
Translation Steps:
- mRNA binds to the small ribosomal subunit.
- Ribosome formation and subsequent tRNA entry.
- Peptide bond formation.
- Translocation (ribosome movement along mRNA).
- Stop codon signals translation termination.

Transcription (DNA to RNA)

Promoter: DNA region where transcription begins.
Transcription Steps:
- RNA polymerase constructs RNA.
- RNA polymerase moves along the DNA in a 3' to 5' direction, producing a 3' to 5' RNA molecule.

Explore key concepts in cell biology regarding surface area to volume ratio and its effect on nutrient transport and cell division. Understand the mechanisms of DNA replication and the roles of various types of RNA during translation. This quiz covers critical biochemical processes necessary for cell function and reproduction.