Cell Structures, Functions and Transport

Cell Basics basic unit of structure and function in living things complex structures most specialized to perform certain functions coordinated functions critical for survival composed of four basic chemicals C, O, H, N plus traces of Fe, Na, K, Ca 60% water

Functions of Cell Structure defines function. 1. basic unit of life 2. protection and support 3. movement 4. communication 5. cell metabolism and energy release 6. inheritance

3 main regions 1. nucleus 2. cytoplasm with organelles 3. nuclear membrane

Section 7-2 Figure 7-5 Plant and Animal Cells Go to Section: Animal Cell

Nucleus the control center holds the DNA – instruction for building proteins necessary for cell reproduction nucleus

3 regions of nucleus 1. Nuclear membrane – double membrane with “moat” in between selectively permeable encloses nucleoplasm Outer and inner membranes form pores. 2. Nucleolus: where ribosomes are assembled

3. chromatin – fibers that form dense, rod- like structures (chromosomes) during cell reproduction composed of DNA and proteins, loosely formed when cell is not dividing

Cytoplasm cellular material outside the nucleus but within the cell membrane site of most cellular activities composed of 3 major components 1. cytosol – semi-transparent fluid composed mostly of water

2. inclusions chemical substances present but not functioning types dependent on function of cell fat droplets in fat cells melanin in the skin primarily stored substances 3. organelles

Organelles mitochondria powerhouse of the cell small, sausage-shaped move, change shape continuously double membrane inner – smooth outer – folds called cristae

Organelles Fluid enzymes and cristae breakdown food. Energy is released and used to form ATP. The more energy a cell requires, the more mitochondria it has. liver and muscles

Organelles Ribosomes tiny round structures site of protein synthesis made up of proteins and one ribosomal RNA some attached, some free-floating

Organelles 3. Endoplasmic Reticulum (ER) minicirculatory system for cell series of tubules and sacs through cytoplasm carry substances from one part of cell to another

Organelles 2 Types: 1. Rough ER studded with ribosomes transports proteins made by ribosomes found in pancreas 2. Smooth ER no ribosomes, no protein synthesis cholesterol synthesis metabolize fat, detox drugs found in liver, testes

Organelles Golgi Apparatus UPS guys of cell composed of closely packed membrane- bound sacs packages, modifies, and transports proteins from rough ER found in salivary glands, pancreas

Organelles Lysosomes intracellular digestive system contain digestive enzymes engulf bacteria other harmful substances and get rid of them removed used and worn out cell parts found in white blood cells

Organelles peroxisomes contain oxydase enzymes to digest fats and detox alcohol, formaldehyde convert dangerous free radicals into H 2 O 2 can mess up protein and nucleic acid structures catalase then converts into H 2 O 2 to water

Organelles cytoskeleton provide framework or skeleton of cell shape, support, intracellular transport, movement made up of protein structures throughout cytoplasm microtubules, intermediate filaments, microfilaments

Organelles centrioles rod-shaped bodies close to nucleus direct formation of mitotic spindle used in cell division centrosomes composed of two centrioles grow into spindle fibers used during cell division

Organelles vacuoles membranous sacs holding area for substances entering the cell

Other Cellular Structures cilia – projections from surface of cell cylindrical shape ex: move mucus in respiratory system flagella – longer than cilia usually only one per cell ex: sperm cells microvilli – extensions on surface of cell membrane increase surface area for absorption ex: intestines, kidneys