CELLS

Cell Theory https://www.youtube.com/watch?v=KuJqqiATlqw

The Cell Theory All living things are made of cells. The cell is the basic unit of all living things. The lowest level of structure capable of performing all the activities of life is the cell All cells come from other cells.

Cells There are no typical cells: Their size, shape, and structure depend on their function.

Additional Cell Info. Unicellular - composed of one cell, all activities occur within the one cell Multicellular - composed of many cells working together, each cell carries out most of the functions of life

Organization in multicellular organisms Tissue Organ Organ system Organism

Viruses and Cells Do not have all the characteristics of life- ABIOTIC! Remind students that viruses must infect living cells to grow and reproduce, taking advantage of the nutrients and cellular machinery of their hosts. This means that all viruses are parasites. Explain that, despite the fact that they are not alive, viruses have many of the characteristics of living things. After infecting living cells, viruses can reproduce, regulate gene expression, and even evolve. Direct students to compare the principal differences between cells and viruses that are shown in the table. Ask: Based on this information, would you classify viruses as living or nonliving? Explain. Sample answer: I would classify viruses as nonliving, because they cannot grow, develop, or obtain energy, and because they cannot reproduce independently.

All Cells Contain DNA Have ribosomes Have cytoplasm Have cell membrane (plasma membrane)

Prokaryotic cells do not have a nucleus lack membrane-bound organelles DNA is not arranged in chromosomes. All unicellular All bacteria

Prokaryotic cells also: can obtain energy from sunlight or from chemicals in their environment. (autotrophic) can obtain energy from other organisms (heterotrophic) contain ribosomes, the site of protein synthesis.

Eukaryotic cells DNA is organized into chromosomes in nucleus true nucleus and membrane-bound organelles Unicellular or multicellular Include- plants, animals, fungi, and protists

Animal cells Do not have a cell wall Have no chloroplasts Multiple small vacuoles Some have cilia or flagella Have centrioles

Plant cells Have cell wall Have chloroplasts Large central vacuole

PARTS OF THE CELL

CELL MEMBRANE OR plasma membrane regulates passage of substances in/out of cell selectively permeable

Cytoplasm fluid material inside the cell contains molecules and organelles, exclusive of the nucleus is bound by the cell membrane.

CILIA Hair-like structures Usually function in locomotion Found in large numbers and relatively short Ex: respiratory cells use to move mucous past them

FLAGELLA Bundles of microtubules that extend through the cell membrane Function in cell locomotion long singular or few Ex: one-celled animals use to move forward, sperm uses to swim forward

centrioles Used in cell reproduction “L” shaped, near nucleus

Nucleus contains DNA - controls cell involved in reproduction of cell and protein synthesis surrounded by a nuclear membrane with pores to allow passage of materials

Nucleolus Located in the nuclear membrane Site of ribosomal synthesis

Endoplasmic Reticulum ER (endoplasmic reticulum) Network of membranous tubes throughout the cytoplasm functions to transport molecules (usually proteins or lipids) folded and connects to nucleus

2 types Rough ER - has ribosomes, protein synthesis Smooth ER - no ribosomes, lipid synthesis

Ribosomes Ribosome located on endoplasmic reticulum, on nucleus, or floating free in cytoplasm site of protein synthesis composed of rRNA

Golgi Bodies Golgi Bodies stacked flattened sacs (cisterns) sort, package, deliver proteins Like the “post office” of the cell

Mitochondria Mitochondria rod shaped sacs with inner folds called cristae powerhouse of cell, releases energy from food cells needing lots of energy have lots (muscle, liver, etc…) Contains mitochondrial DNA Located throughout cytoplasm

Lysosomes Lysosomes contain digestive enzymes to break down old parts and foreign materials “clean up crew” of cell

Vacuoles Membrane-bound storage compartments (for food, water, or waste) Similar to storage bag Plant cells usually have a large, central water vacuole

Chloroplast Typically found in plant and algal cells Contains Chlorophyll (green) Site of photosynthesis (energy from light is converted into chemical energy in glucose) Contains DNA

Cell Wall Located outside the cell membrane usually in plants Composed of cellulose (a polysaccharide) Provides structure and support for plant

Plants Vs FUNGI FUNGI PLANTS Heterotrophs: Decomposers Yeast is unicellar while other fungi are multicellular Cell wall- made of chitin Autotrophs- use photosynthesis All members are multicellular Cell wall is made of cellulose