Presentation on theme: "A View of the Cell From Molecules to Cells The Evolution of Cells Life arose in the oceans Molecules collide and reactions take place Larger biomolecules."— Presentation transcript:
A View of the Cell
From Molecules to Cells The Evolution of Cells Life arose in the oceans Molecules collide and reactions take place Larger biomolecules form (nucleic acids, lipids …) Membranes spontaneously form from lipid materials – provides a boundary Cells begin to replicate; transfer genetic material
Why do we study cells?
The Cell Theory The cell theory is made up of three main ideas: 1.All organisms are composed of one or more cells 2.The cell is the basic functional unit of organisms Schleiden – botanist (1838) - all plants are composed of cells Schwann – zoologist (1839) - all animals are composed of cells 3.All cells come from preexisting cells Virchow – physician (1855) - all cells come from other cells
Activities of life Most everything you think of a whole organism needing to do, must be done at the cellular level… –reproduction –growth & development –energy utilization –response to the environment –homeostasis
Diversity of Cells Relationship between structure & function
ALL CELLS… contain cytoplasm ( fluid-filled interior ) are surrounded by a plasma membrane contain DNA (genetic material) in the form of chromosomes/chromatin have ribosomes (organelles that make proteins)
Two Cell Types Prokaryotic = no true nucleus –1 st to evolve –Bacterial cells –no membrane bound organelles –Smaller size Eukaryotic – has a nucleus –contain membrane bound organelles –much larger – classified as either plant or animal cells
PROKARYOTIC CELL - BACTERIA ONLY Ribosomes DNAPlasma Membrane Cytoplasm
What jobs do cells have to do? –transport materials, maintain homeostasis Take in what is needed; get rid of waste –make proteins proteins control every cell function –make energy for daily life; for growth –build more cells growth reproduction repair
Maintaining Homeostasis Homeostasis = regulation –maintenance of a stable internal environment Requires bringing in & storage of needed materials Transporting materials to their intended destination Elimination of waste materials
don’t digest a biomolecule – instead biomolecule collects in lysosomes –lysosomes fill up with undigested material lysosomes grow larger & larger –eventually disrupt cell & organ function Tay-Sachs disease –lipids build up in brain cells –child dies before age 5 Tay-Sachs What happens if an organelle (like a lysosome) doesn’t work?
Making Proteins: The Endomembrane system
DNA RNA ribosome endoplasmic reticulum vesicle Golgi apparatus vesicle protein on its way! protein finished protein Making Proteins TO: nucleus
Making Energy Mitochondria & Chloroplasts BOTH: –transform energy –double membranes –contain own DNA –self-replicate Dividing Bacteria Dividing mitochondria
Endosymbiotic theory Mitochondria & chloroplasts were once free living bacteria –became engulfed by a larger eukaryote –evolutionary advantage for both one supplies energy the other supplies raw materials & protection Lynn Margulis U of M, Amherst 1981 | ??
Endosymbiosis Evolution of eukaryotes Early PROKARYOTE Early EUKARYOTE Engulfing Aerobic Prokaryote mitochondria Engulfing photosynthetic Prokaryote mitochondria chloroplast ANIMAL CELLS PLANT CELLS