Human Physiology Chapter 2 Cell Structure & Function

Question 1

what are biomolecules?

Answer 1

• molecules made by living things
• contain carbon

Question 2

What are the 4 basic types of biomolecules?

Answer 2

• Carbohydrates
• Lipids
• Amino acids and proteins
• Nucleotides

Question 3

what are carbohydrates composed of?

Answer 3

• carbon
• hydrogen
• oxygen
• the general formula: Cn(H2O)n = (CH2O)n

Question 4

What are the 3 types of carbohydrates?

Answer 4

• Monosaccharides
• Disaccharides
• Polysaccharides

Question 5

how many cells are in the body?

Answer 5

100 trillion

Question 6

what are all cells derived from?

Answer 6

• fertilized ovum

Question 7

how many types of cells are there?

Answer 7

• 200
• 4 general categories

Question 8

what is a plasma membrane?

Answer 8

• Barrier between cell and external environment
• Fluid inside cell = intracellular fluid (ICF)
• Fluid outside cell = extracellular fluid (ECF)

Question 9

what are the internal components of a cell?

Answer 9

• Nucleus
• Cytoplasm
  
  • Cytosol
  • Organelles

Question 10

what does the structure of the plasma membrane consist of?

Answer 10

The fluid mosaic model:
- Phospholipid bilayer
* Cholesterol
* Membrane proteins
* Membrane carbohydrates

Question 11

what is a phospholipid to a cell?

Answer 11

• basic structure of a membrane
• barrier to passage of water-soluble substances between ICF and ECF
• Provide fluidity to the membrane, especially within
  a layer

Question 12

are phospholipids impermeable to water?

Answer 12

• yes
• doesn’t allow water in

Question 13

what are the functions of a phospholipid?

Answer 13

• Barrier to passage of water-soluble substances between ICF and ECF
• Provide fluidity to the membrane, especially within a layer

Question 14

define aquaporins?

Answer 14

• allow water through
• integral membrane proteins

Question 15

what is the function of cholesterol in the cell?

Answer 15

• adds fluidity to the cell membrane
  - Interferes with hydrophobic interactions between phospholipids
  - Prevents crystallization of phospholipids
• decrease permeability of the membrane to water

Question 16

define amphipathic.

Answer 16

• having both hydrophilic and hydrophobic parts

Question 17

how do you isolate proteins

Answer 17

• the membrane must be disrupted

Question 18

what are transmembrane proteins?

Answer 18

• channels
• carrier proteins

Question 19

what is the function of a membrane carbohydrates?

Answer 19

• covalently bound to membrane lipids or proteins
• help with cell recognition
  ex: glycoproteins, glycolipids

Question 20

what is the structure of the nucleus?

Answer 20

• Nuclear envelope
• Nuclear pores
• Nucleolus: Site of ribosomal RNA (rRNA) synthesis

Question 21

what is the function of the nucleus?

Answer 21

• transmission and expression of generic info
• contains DNA: stores genetic code
• transcribes DNA to RNA: which is necessary to express the genetic code

Question 22

what is cytosol?

Answer 22

• fluid of the cell

Question 23

what is the function of the cytosol?

Answer 23

• location of specific chemical reactions
• storage of fat and carbs
• storage of secretory vesicles

Question 24

what are organelles?

Answer 24

• specialized structures that perform various jobs inside cells

Question 25

what is the function of organelles?

Answer 25

- membrane separates the structure from the cytosol

Question 26

what is a endoplasmic reticulum (ER)

Answer 26

- a network of membranous tubules within the cytoplasm of a eukaryotic cell, continuous with the nuclear membrane. It usually has ribosomes attached and is involved in protein and lipid synthesis.

Question 27

what does a rough ER look like?

Answer 27

- Flattened sacs * Granular appearance due to ribosomes

Question 28

what does a Smooth ER look like?

Answer 28

* Tubules * Smooth appearance * Lumens of the two ERs are continuous

Question 29

where does rough ER function?

Answer 29

- in the synthesis of proteins to be packaged into vesicles

Question 30

where does smooth ER function?

Answer 30

- in lipid synthesis, including triglycerides and steroid -

Question 31

what is the function of rough ER

Answer 31

-they export things out of the cell - destined for certain organelles

Question 32

what are the functions of smooth ER

Answer 32

- Stores calcium * Specialized in some cells - Example: Smooth ER in the liver contains detoxification enzymes

Question 33

what is the function of the golgi apparatus?

Answer 33

Post-translational processing of proteins * Packaging of proteins (and other molecules) into vesicles and directing them to the target

Question 34

what is the function of the mitochondria?

Answer 34

- "Power house "of the cell (generates ATP) * Enzymes of the Krebs cycle in the matrix * Electron transport chain on the cristae of the inner membrane

Question 35

what is a lysosome?

Answer 35

- an organelle in the cytoplasm of eukaryotic cells containing degradative enzymes enclosed in a membrane

Question 36

what are the functions of lysosomes?

Answer 36

- Contain enzymes that degrade cellular or extracellular debris

Question 37

what two processes degrade extracellular debris

Answer 37

- Endocytosis * Phagocytosis

Question 38

what do peroxisomes do?

Answer 38

- Degrade certain waste molecules Ie: * Amino acids * Fatty acids * Toxic foreign substances

Question 39

what is Tay - Sachs disease?

Answer 39

- Genetic disorder * Lysosomal enzymes are less effective than normal * Buildup of specific lipids (gangliosides) results in vision loss * Easily startled (hallmark of disease) * Progression: Paralysis, deafness, seizures, death * Most common in persons of Ashkenazi Jewish heritage

Question 40

what are the functions of the cytoskeleton?

Answer 40

- Mechanical support and structure * Intracellular transport of materials * Suspension of organelles * Formation of adhesions with other cells * Contraction * Movement

Question 41

define cytoskeleton?

Answer 41

- Lattice of fibrous proteins on a cell

Question 42

what are the filaments of a cytoskeletal?

Answer 42

- Microfilaments * Intermediate filaments * Microtubules

Question 43

what are the functions of microfilaments?

Answer 43

* Muscle contraction * Amoeboid-like movements * Separation of cytoplasm during cell division * Structural support for cell projections * Microvilli * Hair cells (specialized microvilli) made of actin

Question 44

what are the common types of intermediate filaments?

Answer 44

- Myosin * Keratin - 10 nm in diameter

Question 45

what are the functions of microtubules?

Answer 45

Mitotic spindle * Major component of cilia and flagella * Cilia * Respiratory tract, oviduct * Flagella * Sperm 25 nm in diameter

Question 46

what are non-membranous organelles?

Answer 46

* No membrane * Ribosomes * Vaults * Centrioles * Cytoskeleton

Question 47

what are ribosomes?

Answer 47

Ribosomes = rRNA and proteins * Very small (25 nm) * Important in protein synthesis * Fixed * Attached to rough endoplasmic reticulum * Free * Loose in cytosol

Question 48

define the non-membranous organelle vaults

Answer 48

Barrel-shaped organelle * May function in the transport of molecules between the nucleus and the cytoplasm * Linked to programmed cell death (apoptosis) * Possess vault RNA (vRNA)