Review: Cell Membrane Cell membrane – selectively permeable phospholipid bilayer Controls what...
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Transcript of Review: Cell Membrane Cell membrane – selectively permeable phospholipid bilayer Controls what...
![Page 1: Review: Cell Membrane Cell membrane – selectively permeable phospholipid bilayer Controls what enters and leaves a cell Cell communication (carbohydrate.](https://reader036.fdocuments.in/reader036/viewer/2022082816/56649d365503460f94a0e164/html5/thumbnails/1.jpg)
Review: Cell MembraneCell membrane – selectively permeable phospholipid
bilayer• Controls what enters and leaves a cell• Cell communication (carbohydrate chains)• Protective barrier for cell from its surroundings• Provides anchoring(peripheral proteins) for the cytoskeleton
![Page 2: Review: Cell Membrane Cell membrane – selectively permeable phospholipid bilayer Controls what enters and leaves a cell Cell communication (carbohydrate.](https://reader036.fdocuments.in/reader036/viewer/2022082816/56649d365503460f94a0e164/html5/thumbnails/2.jpg)
How does a Cell Maintain HomeostasisAll cells/organisms require a certain internal environment to
function properly • This is called homeostasis
Main concerns for homeostasis include:• Temperature• pH levels• Ions/salinity• Water levels• Nutrient availability
*these conditions can very minute-to-minute or hour-to-hour*
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Most bodily functions aim at maintaining homeostasis, and the inability to maintain it leads to disease and often death
Temperature• Body prefers 98.6⁰ F• Cold = shake; Pull blood and water into your core
area• Hot = sweat; Send blood and water to your skin
(red color)• Controlled by enzymes unless extreme temps
(denatures the enzyme)
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pH levels• Acids = 0-6; Bases = 8-14 (7 = neutral)• Blood pH level very narrow (7.35-7.45)• Maintained by buffers in the blood (proteins usually)• Affected by oxygen levels • Body pH maintained by lipid buffers, alkaline salts, calcium
from bones and muscles, lymphatic system
Buffers – substances that can balance out too acidic or basic environments
**yeast, molds, fungus, parasites thrive in an acidic body lacking oxygen (anaerobic). They feed on your proteins and fats and poison us with their waste**
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Ions, water, nutrients, and large particles are moved/controlled by cellular transport
Two types of Cellular transport• Passive transport– Does not require energy– Moves from area of high concentration to low concentration– Ex. diffusion, osmosis, facilitated diffusion
• Active transport– Requires energy (ATP)– Moves from an area of low concentration to high
concentration– Ex. pumps, endocytosis, exocytosis, ion channels