Chapter 2 - Basic Components of Living Systems

What is the function of the nucleus and nuclear envelope in a eukaryotic cell?

Contains genetic material (DNA); nucleolus makes rRNA and ribosomes; double membrane with pores controls exchange with cytoplasm

What is the role of the nucleolus?

Site of ribosomal RNA synthesis and ribosome assembly

What is the structure and function of the rough endoplasmic reticulum (RER)?

Flattened membrane sacs with ribosomes; folds, processes, and transports proteins

What is the structure and function of the smooth endoplasmic reticulum (SER)?

Membrane network without ribosomes; synthesises and processes lipids, steroids and carbohydrates

What is the role of ribosomes in eukaryotic cells?

80S ribosomes free in cytoplasm or attached to RER; site of protein synthesis (translation of mRNA)

What is the function of the Golgi apparatus?

Stack of flattened sacs; modifies and packages proteins/lipids into vesicles for transport or secretion; makes lysosomes

What is the function of vesicles?

Membrane-bound sacs that transport substances within cells or to the cell surface

What is the function of lysosomes?

Contain hydrolytic enzymes; digest waste, pathogens, and old organelles

What is the structure and function of mitochondria?

Double membrane; inner membrane folded into cristae; matrix contains enzymes; site of aerobic respiration and ATP production

What is the structure and function of chloroplasts (plant/algal cells)?

Double membrane organelles with thylakoids (stacked as grana) in stroma; site of photosynthesis

What is the function of the cell surface (plasma) membrane?

Phospholipid bilayer with proteins and cholesterol (fluid mosaic); controls entry/exit of substances; cell signalling

What is the structure and function of the cell wall (plants/fungi)?

Plant cell wall: cellulose; fungal cell wall: chitin; provides mechanical support and protection

What is the function of centrioles in animal cells?

Pair of cylindrical microtubules; organise spindle fibres during cell division

What is the role of cilia and flagella?

Microtubule-based structures; cilia move substances across cell surfaces; flagella move whole cells

What is the role of the cytoskeleton?

Network of microtubules and microfilaments; provides mechanical support, maintains shape, enables organelle/vesicle movement and cell division