Cells

Question 1

What are the two general classes of cells in the body?

Answer 1

Sex Cells, Somatic Cells

Question 2

Describe the structure of a typical somatic cell

Answer 2

Intracellular: inside of the cell
Extracellular: surrounding environment outside of the cell

Question 3

Describe the structure of the plasma membrane

Answer 3

Consists of

• Lipids: phospholipids form phospholipid bilayer. Hydrophilic head and Hydrophobic tail
• Proteins: integral (span membrane) and peripheral (bound to inner/outer surface)
• Cholesterol
• Carbohydrates

Question 4

Describe the function of the plasma membrane

Answer 4

-Physical barrier between intracellular/extracellular environment
-Regulates exchange of molecules between
intracellular/extracellular environment
-Structural support

Question 5

Describe the phospholipid bilayer

Answer 5

• Phospholipid molecules form 2 layers
• Hydrophilic head (water loving)
• Hydrophobic tail (water fearing)
• Isolates cytoplasm from surround extracellular fluid

Question 6

What is the cytoplasm?

Answer 6

Material between plasma membrane and nucleus

Question 7

What is the cytoplasm composed of?

Answer 7

Cytosol and organelles

Question 8

What is the function of the microvilli?

Answer 8

Increases surface area to facilitate absorption of extracellular materials

Question 9

What is the function of the cytoskeleton

Answer 9

Strength/support: movement of cellular structures and materials

Question 10

What is the function of the cilia?

Answer 10

A sensor: move materials over cell surface

Question 11

What is the function of free ribosomes?

Answer 11

• Scattered in cytoplasm
• Synthesise proteins for release into cytosol
• Protein synthesis

Question 12

What is the function of fixed ribosomes?

Answer 12

• Located on rough endoplasmic reticulum
• Synthesise proteins and pass them to rough endoplasmic reticulum
• Protein synthesis

Question 13

What is the function of the Golgi apparatus?

Answer 13

Storage, alteration and packaging secretory products

Question 14

What is the function of the smooth endoplasmic reticulum?

Answer 14

• No fixed ribosomes

- Synthesises lipids and carbohydrates

Question 15

What is the function of the rough endoplasmic reticulum?

Answer 15

• Contacts nuclear envelope
• Surface contains fixed ribosomes
• Modifies/packages new proteins produced by fixed ribosomes

Question 16

What is the function of the mitochondria?

Answer 16

-Absorbs oxygen, organic molecules and generate ATP (energy), carbon dioxide and water

Question 17

What is the function of the nucleus?

Answer 17

• Controls cell metabolism, storage, processing of genetic information and protein synthesis
• Determines cell structure and function

Question 18

What are the 2 nucleic acids?

Answer 18

Deoxyribonucleic Acid (DNA) and Ribose Nucleic Acid (RNA)

Question 19

What is a gene?

Answer 19

Section of a DNA strand that specifies the amino acids needed to produce a specific protein

Question 20

Describe transport of molecules across the plasma membrane

Answer 20

Selectively permeable

-permits free passage of some substances and prevents passage of others

Question 21

What is a chromosome?

Answer 21

Proteins that carry genetic information in the form of genes

Question 22

What is the difference between passive and active transport of molecules across the plasma membrane?

Answer 22

• Passive transport requires no energy

- Active transport requires energy in form of ATP

Question 23

What are the types of passive transport?

Answer 23

• Diffusion
• Osmosis
• Facilitated diffusion

Question 24

What are the types of active transport?

Answer 24

• Endocytosis
• Exocytosis
• Active transport

Question 25

Describe diffusion

Answer 25

-Net movement of a substance from an area of higher concentration to an area of lower concentration (down the concentration gradient) -Simple diffusion (gases/lipid soluble molecules) -Channel-mediated diffusion (water soluble molecules/ions)

Question 26

Describe osmosis

Answer 26

Diffusion of water across a membrane

Question 27

Describe facilitated diffusion

Answer 27

Integral proteins bind specific ions or organic substrates and carry them across the plasma membrane (down their concentration gradient)

Question 28

Describe active transport

Answer 28

Integral proteins bind specific ions and carry them across the plasma membrane (up/against their concentration gradient)

Question 29

What is the sodium-potassium exchange pump?

Answer 29

Energy (ATP) is used to pump sodium and potassium across the plasma membrane

Question 30

Describe exocytosis

Answer 30

Vesicle fuses with the plasma membrane to move substances out of the cell

Question 31

Describe endocytosis

Answer 31

Extracellular materials are packaged in vesicles at the plasma membrane and transported into the cell

Question 32

What are the types of endocytosis?

Answer 32

- Receptor-mediated endocytosis (hormones) - Pinocytosis: cell drinking (nutrients) - Phagocytosis: cell eating (bacteria)

Question 33

What are the 5 types of intracellular communication

Answer 33

- Endocrine - Paracrine - Autocrine - Synaptic - Direct

Question 34

Describe endocrine communication

Answer 34

Cell releases a chemical message (hormone) into the bloodstream to affect the activity of specific (target) cells in another part of the body

Question 35

Describe paracrine communication

Answer 35

Cell releases a chemical message (paracrine) into the extracellular fluid to transfer information from cell to cell

Question 36

Describe autocrine communication

Answer 36

When chemical messages (autocrines) affect the same cells that secrete them

Question 37

Describe synaptic communication

Answer 37

Neuron releases a chemical message (neurotransmitter) at a chemical synapse with target cell

Question 38

Describe direct communication

Answer 38

-Between two cells of the same type, and the cells must be in physical contact -Exchange ions across gap junction via diffusion

Question 39

Describe difference between mitosis and meiosis

Answer 39

- Mitosis: produce 2 daughter cells, 46 chromosomes in each cell - Meiosis: produce 4 daughter cells, 23 chromosomes in each cells