Cells 2

Cilia

Hair-like projections
Movement: Moves substances across cell surfaces
Examples: Mucus removal in respiratory tract, egg movement in fallopian tubes

Villi

Finger-like projections
Covered with epithelial cells, often with microvilli on the surface
Absorption: Increases surface area for nutrient absorption

Microvilli

Tiny, hair-like projections
Actin filaments inside
Surface Area Increase: Enhances absorption and secretion

What is RNA Polymerase and What is its Function?

Definition: RNA Polymerase is an enzyme that synthesizes RNA from a DNA template during transcription.

Function:
Binding: Attaches to the promoter region of a gene.
Unwinding: Unwinds the DNA helix.
Synthesis: Adds RNA nucleotides complementary to the DNA template.
Termination: Detaches once the gene is fully transcribed.

Location:

Eukaryotes: Nucleus
Prokaryotes: Cytoplasm

What is RNA Polymerase and What is its Function?

Definition: RNA Polymerase is an enzyme that synthesizes RNA from a DNA template during transcription.

Function:
Binding: Attaches to the promoter region of a gene.
Unwinding: Unwinds the DNA helix.
Synthesis: Adds RNA nucleotides complementary to the DNA template.
Termination: Detaches once the gene is fully transcribed.

What is Translation and Where Does it Occur?

Translation is the process of building a polypeptide (protein) using mRNA as a template at the ribosome.

Initiation: mRNA binds to a ribosome; the ribosome locates the start codon (AUG).
Elongation: tRNA brings amino acids to the ribosome, forming a polypeptide chain.
Termination: Ribosome encounters a stop codon, releasing the completed polypeptide.

Location:
Eukaryotes: Cytoplasm, at ribosomes (free or ER-bound)
Prokaryotes: Cytoplasm

Define DNA and its Role in Protein Synthesis

DNA (Deoxyribonucleic Acid) is a double-stranded molecule containing genetic instructions.

Genetic Information: DNA encodes the instructions for proteins.
Process: DNA is transcribed into mRNA, which is then translated into a protein.

Define RNA and Its Types

RNA (Ribonucleic Acid): Single-stranded nucleic acid crucial for translating genetic information.

Types:

mRNA (Messenger RNA): Carries genetic code from DNA to ribosome for protein synthesis.

rRNA (Ribosomal RNA): Forms ribosomes and catalyzes protein synthesis.

tRNA (Transfer RNA): Transfers amino acids to ribosomes based on mRNA sequence, ensuring correct protein formation.