Unit 3.1 Cell Theory

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3.1-Cell Theory

Improvements allowed scientists to see cells in greater and greater detail and enabled them to discover cells in all types of living matter.
Eukaryotic cells have a nucleus and membrane-bound organelles; prokaryotic cells do not.
Once it was understood that cells were the basic building blocks of living matter, scientists could concentrate on describing different types of cells and discovering the relationship between cell type and cell function. One way to do this is to isolate the cell itself.
Both are basic units, or building blocks. The atom is the basic unit of matter, while the cell is the basic unit of living organisms.
It would not kill bacteria because bacteria do not have a nucleus, so there are
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The nucleus is surrounded by a double membrane with pores that connect its interior to the cytoplasm. DNA and the nucleolus are located inside the nucleus.
A mitochondrion supplies energy to a cell by releasing the energy stored in food molecules. The outer membrane surrounds a highly folded inner membrane where the chemical activity occurs. It has its own ribosomes and DNA.
The cell wall protects, supports, and shapes a plant cell, and regulates what moves into the cell. The cell walls of multiple cells can help support the entire plant.
Both membrane-bound organelles have their own DNA and help make energy available to the cell.
All are composed of membrane-enclosed chambers. The surface area of each is greatly increased by folds and layers.
Increased amounts of smooth ER in the liver cells suggests that the cells have responded to increased amounts of toxins by producing more smooth ER to handle the processing.
3.3-Cell
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A molecule diffuses down its concentration gradient by moving from a region of higher concentration to a region of lower concentration.
No energy is needed because the molecules move down a concentration gradient. hypertonic Both are proteins and may work with only specific molecules. In addition, both may require a change in shape to accomplish their function.
Pure water would be hypotonic relative to the contents of blood cells, so water would rush into the blood cells and could cause the cells to burst. The saline solution is isotonic relative to the cell contents.
3.5-Active Transport, Endocytosis, and Exocytosis

Pumps require energy, transport a molecule against its concentration gradient, and change shape upon binding. A protein channel does not change shape or require energy. It allows certain molecules to diffuse through it, down their concentration gradient.
They require energy input; diffusion does not. They also enable larger particles to enter a cell, particles that are too large to diffuse across a cell