Cell Biology & Cell Organelles

Anton von Leeuwenhoek (1674) Get Hooke-d on Cells! Scientist Discovery Robert Hook (1665) Described the empty spaces between cork as “cells” Actually viewed the cell walls of dead cells Anton von Leeuwenhoek (1674) First observed a living cell (identified bacteria) John Dalton (1808) Atomic Theory All matter is made of atoms Louis Pasteur (1864) Living organisms can only arise from other living organisms

Cell Theory Cells are the basic unit of life All organisms are made of one or more cells All cells must come from pre-existing cells The activity of an entire organism depends on the total activity of its independent cells

Prokaryote Cells Pro: before; karyote: nucleus First cells to evolve Do not contain a membrane-bound nucleus Do not contain organelles smaller than a ribosome Bacteria DNA is single, circular strand Cell wall used as a target for antibiotics Pseudomonas Bacteria

Eukaryote Cells Eu: good/true; karyote: nucleus More complex internal structure and includes a nucleus Include membrane-bound organelles Early prokaryotes were engulfed by other prokaryotes and remained within This formed a symbiotic relationship Created a eukaryotic cell Plant, animal, fungi, protists

Nucleus Structure Function Large oval structure in the centre of the cell Bound by the nuclear membrane Contains the chromosomes and the nucleolus Function Control centre of the cell Regulates all activities of the cell

Nucleolus Structure Function Small, dark area within the nucleus Where ribosomes are made

Nuclear Membrane Structure Function Encloses the nucleus of the eukaryotic cell Function Prevents the contents of the nucleus from being spread in the cytoplasm

Nuclear Pores Structure Function Openings in the nuclear membrane Allows contact between the nucleus and cytoplasm Allows ribosomes produced by nucleus (nucleolus) to move into the cytoplasm

Chromosomes Structure Function Threadlike structures found in the nucleus Function Made of DNA which carries genetic information DNA coils and become visible during cell division Directs cell activities Hereditary material Chromosome = DNA + protein

Cell Membrane Structure Function Bilayer of phospholipids with proteins embedded within it Fluid and flexible Phospholipid Hydrophilic head Hydrophobic tail Function Regulates the passage of materials in and out of the cell

Cytoplasm Structure Function Everything between the cell and nuclear membrane Consists of cytosol (mostly water) and organelles Function Organelles carry out functions within the cell

Cytoskeleton Structure Function Microtubules & Microfilaments Tiny, tube-like fibres found in cytoplasm, cilia, flagella Function Maintains the shape of the cell Microtubules Transport materials throughout cytoplasm Microfilaments Help provide shape and movement for cells

Organelles - Mitochondria Structure Rod-shaped Smooth outer membrane with a greatly folded inner membrane (cristae) which increases the surface area Function Powerhouse of the cell Where food molecules are broken down and their energy used to make special energy-rich molecules

Organelles - Ribosome Structure Function Small, grain-like body made primarily of RNA Lack a membrane May be attached to endoplasmic reticulum or floating freely in cytoplasm Made in the nucleolus Function Site of protein synthesis

Organelles – Endoplasmic Reticulum Structure System of clear, tubular passageways which spreads through cytoplasm Smooth: No ribosomes attached Rough: Ribosomes attached Function Smooth: Transports proteins produced by ribosomes throughout the cell Rough: Transports fats and proteins (synthesized on SER) throughout the cell

Organelles – Endoplasmic Reticulum Smooth Rough

Organelles – Golgi Apparatus Structure Membranous sacs piled on top of each other Function Modifies, collects, packages, and distributes proteins made in one location and used in another Proteins released by exocytosis

Organelles – Lysosome Structure Function Small, round sac in cytoplasm Contains digestive enzymes Formed by the golgi apparatus Function Suicide sacs Breaks down food, old cell parts, and dead or injured cells

Organelles – Vacuoles Structure Function Sac-like structures Larger in plants than animals Function Store water, salts, proteins, and carbohydrates. Allow plants to support leaves and flowers

Organelles – Plastids Structure Function Found only in plants Similar structure to the vacuole Function Chloroplast: use sunlight for energy Leukoplast: store starch granules Chromoplast: Store pigment molecules (orange, yellow)

Organelles – Chloroplast Structure Large, green structure in the cytoplasm Contains chlorophyll Thylakoid: outer membrane Stroma: inner membrane Grana: stacks of chlorophyll Function Captures energy in sunlight and uses it to produce food

Organelles – Centrioles Structure Two bundles of fibres at right angles Found in animal cells only Present during mitosis (cell division) Function Migrate to poles during mitosis Microtubules form between centrioles to pull chromosomes apart

Plant vs. Animal Cells Plant cells Animal Cells Cell wall made of cellulose for support Chloroplasts which convert energy through photosynthesis Large vacuoles No lysosomes Animal Cells Centrioles aid in cell division Small vacuoles

Animal Cells

Plant Cell