Cell Organelles

Cytoplasm• Colloid – between the solid and the liquid state

• 80% water + salts, proteins, enzymes

• Enzymes- speed up the breakdown of organic matter and aid in metabolic activities

• Gives the cells its shape and determines the location of organelles within the cell

Nucleus• Regulates the expression of genes & copying of DNA

• Composed of: * nuclear membrane * nucleolus * chromosomal apparatus * nucleoplasm

Nuclear Membrane• Double layer – perichondrial liquid

• External membrane – ER + ribosomes

• Pores – large molecules like DNA & RNA

• Less selective than the cell membrane – exchange between the cytoplasm and nucleoplasm

Nucleoplasm- Liquid within the nucleus

- Denser than the cytoplasm

- Contains ribosomes: through the nuclear membrane in cytoplasm

ChromosomesChromatin-> chromosomes: genetic

material- Diploid – ½ mother & ½

father

- 44 (22 pairs) autosomes & 2 sex chromosomes

- Homologue – shape and size

Chromosomal apparatus

Nucleolus-Lack membrane

-Synthesis of ribosomes

-RNA + proteins

- Response to stress

Ribosomes- Round or oval

-Are found in the outer later of the ER, nuclear membrane, cytoplasm

- Protein synthesis

Endoplasmic Reticulum- Found in the cytoplasm

- Made of proteins and lipids

- Intracellular transport system

Rough: proteinsSmooth: hormones,

metabolism of hydrates of C, ion transport

Golgi ApparatusMembranous tubules and pouchesVertebrates: 1Plants/Invertebrates: Many

Protein assembly: folds proteins into usable forms / attaches lipids and carbohydrates

LysosomesSingle layer membrane:

permeability

Different shape and size Enzymes: Break down organic matter – proteins, lipids, nucleic acids

MitochondriaDouble layer: lipids and proteins- Inner and outer

- Energy for cellular processes- DNA & RNA - independent

organelles- Binary fission – two new cells

Cytoskeleton

Composed of: -- microtubules -- microfilaments

Movement and shape of the cell

CentrosomeAnimal cells / Lower Plants

Synthesis of microtubules

Plastids

Plant cells – absent in fungi

Production and storage of important chemical compounds

Chloroplasts– green

- photosynthesis

PlastidsChromoplasts – yellow to red-attract pollinators

Leucoplasts – no color- Store of lipids and starch