Endomembrane System FRQ: Cell Functions, Protein Pathway, and Ribosome Location, Biology: Key Concepts in Gene Expression and Cell Organelles

What is the primary function of Cell X?

Movement of a cell or of a substance along its surface (e.g., mucus)

What supports the function of Cell X?

It has a large amount of cilia for movement and a large amount of mitochondria for energy.

What is the primary function of Cell Y?

Secretion/Exocytosis or Protein synthesis/trafficking

What supports the function of Cell Y?

It has a large amount of Rough ER and Golgi, which are involved in protein synthesis and packaging.

What is the pathway for production of a normal transport protein?

Nucleus → ER → Golgi → Plasma Membrane

Where are the ribosomes that synthesize the transport protein located?

Rough endoplasmic reticulum

Gene Expression

The process by which information from a gene is used to synthesize a functional gene product, typically proteins.

Nucleotide

The basic building block of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base.

Purine

A type of nitrogenous base that has a two-ring structure, including adenine (A) and guanine (G).

Pyrimidine

A type of nitrogenous base that has a single-ring structure, including cytosine (C), thymine (T), and uracil (U).

mRNA

Messenger RNA, a type of RNA that carries genetic information from DNA to the ribosome for protein synthesis.

tRNA

Transfer RNA, a type of RNA that transports amino acids to the ribosome during protein synthesis.

rRNA

Ribosomal RNA, a component of ribosomes that helps in the synthesis of proteins.

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing proteins from mRNA at the ribosome.

Ribosome

A cellular structure that facilitates the translation of mRNA into proteins.

RNA Polymerase

An enzyme that synthesizes RNA from a DNA template during transcription.

Codon

A sequence of three nucleotides in mRNA that codes for a specific amino acid.

Amino acid

The building blocks of proteins, which are linked together by peptide bonds.

Anticodon

A sequence of three nucleotides in tRNA that is complementary to a codon in mRNA.

Silent mutation

A change in the DNA sequence that does not alter the amino acid sequence of a protein.

Frameshift mutation

A mutation caused by insertions or deletions that shift the reading frame of the genetic code.

Prokaryote

A unicellular organism that lacks a nucleus and membrane-bound organelles, such as bacteria.

Eukaryote

An organism whose cells contain a nucleus and membrane-bound organelles, including plants and animals.

Endomembrane system

A network of membranes within eukaryotic cells that includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, and vesicles.

Mitochondria

Organelles known as the powerhouses of the cell, responsible for producing ATP through cellular respiration.

Rough endoplasmic reticulum

A type of endoplasmic reticulum studded with ribosomes, involved in protein synthesis and processing.

Smooth endoplasmic reticulum

A type of endoplasmic reticulum without ribosomes, involved in lipid synthesis and detoxification.

Golgi apparatus

An organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Lysosome

An organelle containing digestive enzymes that break down waste materials and cellular debris.

Vacuole

A membrane-bound organelle in plant and fungal cells that stores nutrients, waste products, and helps maintain turgor pressure.

Chloroplast

An organelle found in plant cells that conducts photosynthesis, converting light energy into chemical energy.

(a) Predict the most likely outcome of culturing transformed E. coli in the presence of tetracycline. Justify your prediction.

The cells will still be able to grow and reproduce if they are transformed, because…

Transformed bacteria contain the plasmid making them able to express the tetracycline resistant gene/protein

(b) Draw an “X” on the plasmid template provided below to indicate where the human DNA fragment was most likely inserted. Justify your placement of the inserted human DNA.

The X is on the kanamycin resistant gene (or promoter)

The human DNA disrupted the expression of kanamycin resistance