Cell Biology

Question 1

Tree parts of the cell

Answer 1

Cytoplasm and organelles

Cytoplasmic membrane

Nucleus

Question 2

Plasma membrane

Answer 2

Embedded cholesterol molecules strengthen the membrane and help make the membrane less permeable to water soluble substances

Many types of proteins in the plasma membrane. Perform a variety of functions and vary in shape
•Function as receptors on the cell surface
• aid the passage of molecules and ions
• protrude into the cell provide the cytoskeleton
•proteins have carbohydrates attached are used for cell identification
•cellular adhesion molecules

Question 3

Plasma membrane

Answer 3

The cell membrane regulates the movement of substances in and out of the cell, participate in signal transduction and helps cells adhere to other cells

The cell membrane is extremely thin, flexible and selectively permeable

Question 4

Structure of plasma membrane

Answer 4

A double layer of phospholipids, with fatty acid tails turned inward and the water- soluble heads towards the surface

The phospholipids can move forming a stable fluid film

Molecules that are soluble in lipids can pass through the lipid portion of the membrane while it is impermeable to water soluble molecules

Water soluble molecules need channels made of proteins

Question 5

The cytoplasm

Answer 5

The cytoplasm consists of a clear liquid a supportive cytoskeleton and networks of membranes and organelles

Question 6

Organelles

Answer 6

Endoplasmic reticulum is made up of membranes, flattened sacs and vesicles, and provides a tubular transport system inside the cell

With ribosomes, endoplasmic reticulum is rough ER and functions in protein says theirs and processing
Without ribosome it it smooth ER and functions in lipid synthesis, absorption of fates and metabolism of drugs

Question 7

The Golgi apparatus

Answer 7

Is composed of flattened sacs and refines packages and transports protein formed in the rough ER

Is located near rough Er

Question 8

Mitochondria

Answer 8

Is the power house of the cell and contain enzymes needed for cellular reputation

The inner membranes of ottochondrion is folded into Cristal which hold the enzymes needed in energy transformations to make ATP

Very active cells contain thousands of mitochondria

Mitochondria have their own DNA and reproduce by dividing

Question 9

Lysosomes

Answer 9

Are the rubbish disposal unit of the cell and contain digestive enzymes to brake up old cell components bacteria, nutrient molecules, cholesterol, toxin and drugs

Question 10

Peroxisomes

Answer 10

Contain enzymes that function in the brakedown of lipids and hydrogen peroxide and detoxification of alcohol

Question 11

The centrosome

Answer 11

Is a structure made up of tow hollow cylinders called centrioles that function in the separation of chromosomes during cell division made of nine groups of three microtubules

Question 12

Membrane transport

Answer 12

Plasma membrane is site where movement of substances around the body is controlled

Can be active or passive

Question 13

Passive transport

Answer 13

Diffusion

Facilitated diffusion

Osmosis

Filtration

Question 14

Active transport

Answer 14

Pumps

Endocytosis

Exocytosis

Question 15

Facilitated diffusion

Answer 15

Facilitated diffusion uses membrane proteins that function as carriers to move molecules across the cell membrane

Occurs when membrane itself would be impermeable to the substance so relies upon presence of these specific carriers molecules

Question 16

Osmosis

Answer 16

Is a spicial case of diffusion in which water moves from an area of greater water concentration across a selectively permeable membrane to an area of low water concentration.
The membrane is soluble to water but insoluble to solutes

Question 17

Active transport

Answer 17

Active transport uses ATP to move molecules from areas of low concentration to area of high concentration through carrier molecules in cell membrane

May also be called pumps
40% of energy uses to do this

Particles that are actively transported including sugar, amino acids and sodium, potassium, calcium as well as nutrients molecules in the intestines

Question 18

Endocytosis

Answer 18

Molecules that are too large to be transported by other means are conveyed inside a vesicles that forms from a section of the cell membrane

Exocytosis is the movement of materials out of the cell in a vesicles that fuses with the cell membrane and opens up to the outside to secrete the materials