Unit 1- The working cell

Question 1

How are large biological molecules built and broken?(name the components) and Why broken down this way?

Answer 1

1) not made or broken down all at once, they’re made of smaller pieces called MONOMERS
2) large bio. molecules made or many monomers linked together are called POLYMERS
3) less complicated to pre-synthesize small molecules (or obtain them from the diet) and just attach/detach them

Question 2

Name and describe the process in which large bio. molecules are built

Answer 2

almost always done by dehydration synthesis; building polymers by removing water from between 2 monomers

Question 3

Name and describe the process in which large biological molecules (polymers) are broken

Answer 3

• by hydrolysis
• water is added to break the chemical bond between 2 monomers

Question 4

Name 4 main types of cell-cell junctions

Answer 4

• Desmosomes
• Tight junctions
• Gap junctions
• Plasmodesmata

Question 5

Describe desmosomes and their function

Answer 5

• junctions that attach and hold adjacent cells together
• prevent tearing of tissues under physical stress

Question 6

Describe tight junctions and their function + where

Answer 6

• they hold the membranes of the two adjacent cells very close
  together
• they create a leak-proof seal
  -they can be found in stomach,bladder, BBB (blood brain barrier)

Question 7

name the 4 uses of lipids in nature

Answer 7

• insulation from cold
• energy storage
• hydrophobic barrier
• hormones for cell signaling

Question 8

name the 5 general functions of cell membranes (SARRA)

Answer 8

• Selectively isolate the cell’s internal contents from its external environement
• Attaching cells together
• Regulate the exchange of materials between the inside/outside of the cell or organelle
• Regulate biochemial reactions
• Allow for communication with other cells

Question 9

Name the 4 levels of protein structure

Answer 9

→ Because of the huge variety of amino acids, proteins can have very complex structures.

• primary structure (the simplest)
• secondary structure
• tertiary structure
• quaternary structure (most complex)

Question 10

Name + name the function of ATP with 3 statements

Answer 10

• adenosine triphosphate
• used to store chemical energy for short periods of time
• energy stored in the bonds connects the 3 phosphate molecules
• when those bonds are broken, a HUGE amount of energy is released

Question 11

polymer to monomer?
- proteins
- carbs
- nucleic acids

Answer 11

• amino acids
• simple sugars
• nucleotides

Question 12

Name the 5 classes of membrane protein (ARRET)

Answer 12

• Adhesion proteins
• Recognition proteins
• Receptor proteins
• Enzymatic proteins
• Transport proteins

Question 13

Name 2 ways cell membranes can be different

Answer 13

• different fluidity
• different composition of proteins and phospholipids

Question 14

Name 4 non-membranous cell components (EXCEPTIONS- RCCC)
*trevor’s question

Answer 14

• ribosomes
• cytoskeleton
• centrisomes
• centrioles

Question 15

name the function of adhesion proteins + give 1 example

Answer 15

• attach a cell to either another cell or a solid surface outside of the cell
• ex: integrins are adhesion proteins bindinf to the extracellular matrix

Question 16

name the 3 functions of recognition proteins + give 1 example

Answer 16

• identify the cell as being from the species (or even the individual organism) that it is from
• helps other important cells recognize it as ‘’ being like them’’ (acts as a ame tag for cells)
• often have a carb attached to them, called a glycoprotein
• ex: MHC proteins

Question 17

name 2 steroid functions

Answer 17

• Hormones; for communication between cells → ETC- etsrogen, testosterone, cortisone
• Components of cell membranes → cholesterol for membrane fluidity

Question 18

5 properties of water

Answer 18

1) water can interact with many molecules in many different ways
2)water molecules stick to polar molecules
3) water-based solutions can be acidic, basic or neutral
4) the temperature of water is relatively difficult to change
5)water forms a unique solid

Question 19

the size and polarity of water make it a good solvent because:
*key word: dissolve

Answer 19

-dissolve ionic bonds
-dissolve molecules with polar covalent bonds
-dissolve small, non-polar gases
-important because many substances can be dissolved in a cell’s cytoplasm to participate in chemical recations required for life

Question 20

what are hydrophobic interactions (technically not a chemical bond)

Answer 20

-when large non polar molecules stick together in an aqueous environment
- that is due to the hydrogen-bonding ability of water

Question 21

explain why each property of water is important

Answer 21

1) important to allow cells to create barriers in different aqueous compartments
2) important to allow terrestrial plants to move water from roots to leaves (CAPILLARY ACTION)
3) important because different biochemical reactions in the cells requires different pH conditions
4)important in order for living things to moderate their body temperature
5)important because
1- prevents bodies of water from freezing totally solid
2-allows for marine life in winter and polar areas

Question 22

explain the importance of carbon in biological molecules

Answer 22

the carbon atom makes up the skeleton because of its VERSATILITY
- can bond w up to 4 atoms
- can form single double or triple bonds
- carbon skeletons can have many different shapes

Question 23

what are functional groups + explain their importance in biological molecules

Answer 23

Functional groups are: groups of atoms attached to the carbon skeleton that give every biological molecule its unique properties.
→ less stable, and will react much more readily than the carbon skeleton.
→Determines the behaviour of the biological molecule.
→Most biological molecules use the same general set of functional groups.

Question 24

name the basic characteristic of all lipids (2)

Answer 24

→The many carbon and hydrogen atoms make non-polar covalent bonds with each other.
→Lipids are very hydrophobic because of their size and all the non-polar bonds.

Question 25

name the three major classes of lipids in nature

Answer 25

1) Triglycerides
2) Phospholipids
2) Steroids

Question 26

name 4 common carbs in nature and their function

Answer 26

1) glucose
2) sucrose
3) cellulose
4) glycogen
functions:
of glucose+ fructose
- short term energy storage
-building blocks to make polysaccharides

fct of cellulose:
main structural component of plants + used for protection, unbranched, parallel, every 2nd glucose inverted

fct of glycogen:
polysaccaheride, energy reservoir/storage in animals, branched structure for enzymes to capture energy easily from the ends of the branches

Question 27

How can nucleotides act as signaling molecules (3)

Answer 27

→ The single nucleotide cyclic AMP (cAMP) acts as a signaling molecule.
→ It acts as a chemical signal within one cell, not from one cell to a different cell. An intracellular messenger.
→Often called a second-messenger, because it is often the second signaling molecule to respond after a membrane receptor binds its specific signaling molecule.

Question 28

why can we say that a fatty acid chain has dual properties? + give an example

Answer 28

• because there is a hyphophilic head and a hydrophobic tail in the fatty acid chain
• ex: soap
  → head washes away oils/ dirt (hydrophilic) and tail picks up oil/dirt (hydrophobic)

Question 29

how does systemic signaling work in plants

Answer 29

through transport of signaling molecules through vascular tissues

Question 30

what is the primary role of albumin in eggs

Answer 30

serving as a reservoir of amino acids for the growing embryo to utilize

Question 31

what is the primary role of secondary messenger signaling molecules

Answer 31

Initiating signal transduction cascades within the cytoplasm

Question 32

what structural feature distinguishes phospholipids from triglycerides

Answer 32

Presence of phosphate group
(they both have fatty acids, watch out 4 confusion)

Question 33

what is the function of receptor-mediated endocytosis in cells

Answer 33

Receiving SPECIFIC molecules from the extracellular environment

Question 34

define pynocytosis

Answer 34

The bulk uptake of extracellular fluid and solutes by membrane invagination

Question 35

which type of transport involves the movement of molecules or ions across the cell membrane through protein channels

Answer 35

facilitated diffusion

Question 36

which type of chemical bonding involves the sharing of electrons between atoms

Answer 36

covalent bonding (STRONG bond)

Question 37

which specialized ell-cell junction is responsible for cytoplasmic connection between adjacent plant cells

Answer 37

plasmodesmata

Question 38

explain why water molecules can form hydrogen bonds with each other

Answer 38

made of O atoms (partial negative charge) and made of H atoms (partial + charge), which are required for a H bond to occur