UNIT 1.2

Question 1

Compare the simple differences between Prokaryotes and Eukaryotes

Answer 1

PROKARYOTES:
-Simple structure, no compartmentalisation. 
-No Nucleus, just nucleoid region.
EUKARYOTES:
-Compartmentalised structure.
-Has a nucleus.

Question 2

What kingdom are Prokaryotes in and what are the two subtypes of this kingdom

Answer 2

MONERA
subtypes;
-Eubacteria; traditional bacteria (INC. pathogenic forms)
-Archaebacteria; Extremophiles

Question 3

What are the features of a Prokaryote and what are their corresponding functions ?

Answer 3

• Nucleoid Region; DNA (contains circular strand called genophore).
• Plasma Membrane; Controls the movement of substances in & out of the cell, the membrane is partially permeable.
• Ribosomes (70S); Site of protein synthesis.
• Cytoplasm;Fluid component of the cell, gives the cell shape.
• Cell Wall; Gives the cell shape and prevents bursting.
• Capsule; Encloses the bacterial cell.
• Pilli; Thin protein tubes that enable attachment and conjugation.
• Flagellum; slender projection containing a motor protein, this permits movement of bacteria.
• Plasmid; Autonomous circular DNA molecules that may be transferred between bacteria (Horizontal gene transfer).

Question 4

Outline Binary Fission

Answer 4

• Circular DNA (Genophore) is copied in response to a replication signal.
• The two DNA loops attach to the membrane at opposite sides of the cell.
• The membrane elongates and pinches off (Cytokinesis) forming two daughter cells.

Question 5

Eukaryotes are believed to have evolved from Prokaryotes via which process?

Answer 5

Endosymbiosis

Question 6

What are the 4 Eukaryotic Kingdoms ?

Answer 6

• PROTISTA( Unicellular organisms or multicellular organisms without tissue)
• FUNGI; cell wall made of chitin, obtain nutrition via heterotrophic absorption.
• PLANTAE; cellulose cell wall, obtain nutrition autotrophically.
• ANIMALIA; No cell wall, obtain nutrients via heterotrophic ingestion.

Question 7

Outline the Organelles in a Eukaryotic cell and their corresponding functions.

Answer 7

• NUCLEUS; Stores DNA as chromatin (Nucleolus site of ribosome assembly)
• ENDOPLASMIC RECTICULUM; Transportation of materials between organelles (Rough = Proteins, Smooth = Lipids).
• GOLGI APPARATUS; Sorting,storing,modification and export of secretory products.
• MITOCHONDRIA; Site of aerobic respiration.
• RIBOSOMES(80S); Polypeptide synthesis (Translation)
• PLASMA MEMBRANE; Semi - Permeable, selective barrier.
• PEROXISOME; Membranous sac containing a variety of catabolic enzymes.
• CENTROSOME; Radiating microtubules form spindle fibres and contribute to cell division (mitosis / meiosis)
• LYSOSOME(Animal Only); Hydrolysis of macromolecules.

Question 8

Outline the plant exclusive organelles and their corresponding features.

Answer 8

• CHLOROPLAST; Contains double membrane and Internal stacks of thylakoids. Site of photosynthesis.
• VACUOLE; Fluid filled internal cavity, maintains hydrostatic pressure.
• CELL WALL; Support and mechanical strength, prevents excessive water uptake.

Question 9

What is a ‘Cell Micrograph’?

Answer 9

A micrograph is a photo or digital image taken through a microscope to show a magnified image of a specimen.

Question 10

Why may the shape of organelles differ between micrographs ?

Answer 10

specific shapes may vary depending on the location of cross-sections.