Ap Biology Unit 9 Study Guide
1. Cells structure and Organisation
1.1 Plant Cells and Animal Cells:
Fig.1.0 Basic structures of an animal cell and a plant cell. 1. • • • Cell wall: Porous. Permeable. Non-living structure made of cellulose.
2. Cell membrane/Plasma membrane • Semi-permeable/Partially permeable(Only certain parts can pass through it and some aren't able).
3. • • • Cytoplasm Contains cell organelles. Food substances. Mostly H2O.
4. Vacuole/Sap vacuole/Large central vacuole • Mostly H2O. 5. Nucleus • Controls all activities of a cell. 6. Chloroplasts • Contains green pigment called Chlorophyll which is important for doing Photosynthesis. 7. • • • Differences between plant cells and animal cells Only plant cells have cell wall. Only plant cells have …show more content…
Homeostasis
Monday, November 24, 2008 10:14 PM
10.1 Homeostasis. 1. Homeostasis is the maintenance of a constant internal environment. 2. • • • For any homeostatic control to occur there must be: a stimulus which is a change in the internal environment, a receptor which can detect the stimulus, an automatic or self-regulatory corrective mechanism, which bring about a negative feedback. Homeostasis may include the regulation of the following: Blood glucose level, Blood water potential, Temperature.
10.2 Blood glucose regulation.
3. • • •
1. The regulation of blood glucose level is done by the pancreas. 2. Homeostatic control of blood glucose …show more content…
1. The regulation of temperature is done by the skin. 2. The skin:
Fig.10.3 The structure of the skin. 3. When the body is exercising vigorously or when the surrounding is hot: 1) Thermoreceptors in the skin detect an increase in environmental temperature or heat sensors in the hypothalamus detect a rise in the temperature of the blood. 2) The sweat glands increase the production of sweat. 3) Vasodilation, increases the internal diameter of blood vessels so that more blood is brought to the capillaries. 4) Body loses heat as sweat evaporates. 5) Body loses heat as more blood is brought to the skin surface, leading to increased heat loss by conduction, convection and radiation. 6) Metabolic rate is lowered leading to the decreased heat production by cells. 7) Body temperature is lowered. 4. When the body is at rest or when the surrounding is cold: 1) Thermoreceptors in the skin detect decrease in the environmental temperature or heat sensors in the hypothalamus detect drop in temperature of blood. 2) The sweat glands stop production of sweat. 3) Vasoconstriction, reduces the internal diameter of blood vessels so that less blood is brought to the capillaries. 4) Body gains heat as erector muscles in the skin contract causing the hairs to stand up, creating a layer of air which will act as insulation. 5) Skeletal muscles contract and relax repeatedly; this shivering resulting in production of heat. 6) Less blood is brought to the skin surface
1.1 Plant Cells and Animal Cells:
Fig.1.0 Basic structures of an animal cell and a plant cell. 1. • • • Cell wall: Porous. Permeable. Non-living structure made of cellulose.
2. Cell membrane/Plasma membrane • Semi-permeable/Partially permeable(Only certain parts can pass through it and some aren't able).
3. • • • Cytoplasm Contains cell organelles. Food substances. Mostly H2O.
4. Vacuole/Sap vacuole/Large central vacuole • Mostly H2O. 5. Nucleus • Controls all activities of a cell. 6. Chloroplasts • Contains green pigment called Chlorophyll which is important for doing Photosynthesis. 7. • • • Differences between plant cells and animal cells Only plant cells have cell wall. Only plant cells have …show more content…
Homeostasis
Monday, November 24, 2008 10:14 PM
10.1 Homeostasis. 1. Homeostasis is the maintenance of a constant internal environment. 2. • • • For any homeostatic control to occur there must be: a stimulus which is a change in the internal environment, a receptor which can detect the stimulus, an automatic or self-regulatory corrective mechanism, which bring about a negative feedback. Homeostasis may include the regulation of the following: Blood glucose level, Blood water potential, Temperature.
10.2 Blood glucose regulation.
3. • • •
1. The regulation of blood glucose level is done by the pancreas. 2. Homeostatic control of blood glucose …show more content…
1. The regulation of temperature is done by the skin. 2. The skin:
Fig.10.3 The structure of the skin. 3. When the body is exercising vigorously or when the surrounding is hot: 1) Thermoreceptors in the skin detect an increase in environmental temperature or heat sensors in the hypothalamus detect a rise in the temperature of the blood. 2) The sweat glands increase the production of sweat. 3) Vasodilation, increases the internal diameter of blood vessels so that more blood is brought to the capillaries. 4) Body loses heat as sweat evaporates. 5) Body loses heat as more blood is brought to the skin surface, leading to increased heat loss by conduction, convection and radiation. 6) Metabolic rate is lowered leading to the decreased heat production by cells. 7) Body temperature is lowered. 4. When the body is at rest or when the surrounding is cold: 1) Thermoreceptors in the skin detect decrease in the environmental temperature or heat sensors in the hypothalamus detect drop in temperature of blood. 2) The sweat glands stop production of sweat. 3) Vasoconstriction, reduces the internal diameter of blood vessels so that less blood is brought to the capillaries. 4) Body gains heat as erector muscles in the skin contract causing the hairs to stand up, creating a layer of air which will act as insulation. 5) Skeletal muscles contract and relax repeatedly; this shivering resulting in production of heat. 6) Less blood is brought to the skin surface