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معلومات المذكرة

  • نوع الملف: ملف تلخيص
  • المادة: أحياء
  • الصف: التاسع متقدم
  • الفصل الدراسي: الفصل الأول
  • صيغة الملف: pdf متاح للتحميل

 [highlight color=”blue”]صندوق تحميل الملف[/highlight]

Cellular Transport

the movement across the plasma membrane occurs through 2 basic processes: passive transport and active transport

 Active transport is the movement of materials across the plasma membrane from an area of lower concentration to an area of higher concentration, with the use of energy from the cell

carrier-assisted transport (pumps)

carrier proteins embedded in the plasma membrane move ions

Example: The sodium-potassium ATPase pump
(Na+/K+ ATPase pump)

Transports 3 Na+ out of the cell and 2 K+ into the cell

vesicle-mediated transport

vesicles that fuse through the cell membrane moves large materials

Example: endocytosis and exocytosis

a vesicle is a small sac
enclose large materials and can pull

 materials into or out of the cell

Endocytosis

a type of active transport that moves particles into a cell

Exocytosis

type of active transport that moves particles outside a cell

The difference in concentration of molecules across a space is called the concentration gradient

Active transport is the movement of materials against a concentration gradient and that i
requires the use of energy from the cell

ATP (adenosine triphosphate)

  1. adenine
  2. sugar
  3. 3 phosphate groups

 Passive Transport is the movement of materials through the plasma membrane from an area of higher concentration to an area of lower concentration, that does not require energy from the cell

simple diffusion
movement of small or nonpolar molecules such as oxygen and carbon dioxide across the plasma membrane

osmosis

movement of water molecules across the plasma membra

Facilitated diffusion

movement of large or charged molecules, such as proteins and ions, through water-filled transport proteins

Based on the solute concentration, solutions can be categorized as isotonic, hypotonic, and hypertonic solutions

  • Isotonic solution the concentration of solute is the same inside and outside the cell
  • Hypotonic solution the concentration of the solute outside the cell is lower than it is inside
  • Hypertonic solution the concentration of the solute outside the cell is higher than it is inside

Channel proteins
are like pores that open and close and allow ions to diffuse across the plasma membrane

Carrier proteins
carry large molecules, such as glucose, across the plasma membrane by changing shape after they bind to the molecule

At dynamic equilibrium,
the concentration of molecules is the same throughout the space. The movement of particles between the two sides still occurs, but the rate of movement is the same

Main factors that affect the rate of diffusion

A higher concentration can increase the number of collisions between the particles, and this increases the diffusion rate

A higher pressure can increase the collision between the particles, and this increases the diffusion rate

A higher temperature can increase the speed of collisions between the particles and this increases the diffusion rat

 

The Digestive Organs

Esophagus

a hollow muscular tube that connects the pharynx to the stomach

has smooth muscles that lines its walls

cm  long 25

move the food from mouth to the stomach by peristalsis

Stomach

a hollow, muscular sac that connects the esophagus to the small intestine

has three overlapping layers of smooth muscles that line its walls

has capacity of 50 mL when empty and expands to 2 to 4 L when full

Small Intestine

a long tube that connects the stomach to the large intestine

the longest part of the digestive tract, about 7 meters long

has a diameter of 2.5 cm

has smooth muscles that lines its walls

Large Intestine

the final section of the digestive tract

about 1.5 meters long

has a diameter of 6.5 cm

includes the colon, the rectum, and the appendix

1- you swallow

2- the epiglottis covers your trachea

3- the food or drink goes down the esophagus

4- the cardiac sphincter closes after food enters your stomach

5- muscles in the stomach churn food and form chime

6- chime leaves your stomach through the pyloric sphincter

7- much of the chemical digestion takes place in the first part of your small infesting

8- the absorption of nutrients occurs villi in the small intestine

9- the large intestine absorbs water from the undigested food

10- solid waste exit the body through the anus

The Endocrine System

is composed of glands that produce and secrete hormones and functions as a communication system for the body

 ? What are endocrine glands
Endocrine glands are glands that release their hormones directly into the bloodstream

 ? What are hormones
Hormones are chemical messengers that travel in the bloodstream and act on target cells

Types of Hormones

Steroid Hormones

composed of lipids – cholesterol •

can easily pass through the plasma membrane because they are soluble in lipids •

bind to receptors inside the cell •

examples of steroid hormones include: estrogen and progesterone •

Amino Acid Hormones

composed of amino acids •

cannot easily pass through the plasma membrane because they are not soluble in lipids •

bind to receptors on the surface of the cell •

examples of amino acid hormones include: insulin and growth hormone •

Amino acid hormones initiate biochemical
pathway causing the cell to produce
the
 desired response

Steroid hormones act by
entering the nucleus and
activate specific genes

The Endocrine System & Homeostasis

Homeostasis in the body is maintained by internal feedback mechanisms called negative feedback

Negative feedback returns the system
to a set point once it deviates from it

Insulin and glucagon have opposite actions. They maintain the level of glucose in blood by a  negative feedback loop

Thyroid and parathyroid hormones have opposite actions. They maintain the level of calcium in blood by a negative feedback loop

Diabetes

Type 1 Diabetes

little or no insulin is produced by the pancreas
appears by the age of 20

Type 2 Diabetes

the cells of the body do not respond to insulin

occurs after the age of 40

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