Review set 1

Question 1

Structure of water

Answer 1

Water is polar (dipolar) and forms up to four hydrogen bonds with other water molecules

Question 2

Water’s Properties: Thermal Properties (due to hydrogen bonds)

Answer 2

High specific heat : stabilizes environments for life (around them and within them) – a large amount of heat only raises water temp. a small amount – heat energy used to break hydrogen bonds BEFORE individual water molecules heat up
High heat of vaporization: evaporative cooling for organisms

Question 3

Water’s Properties: Cohesive and Adhesive Properties (due to hydrogen bonds)

Answer 3

High surface tension: organisms live on surface/ maintains lung structure (pleural membranes)
Transport in plants: Hydrogen bonds “stick” water molecules together (cohesion) and to other substances (adhesion - such as xylem walls) – allows movement (pull) of water through plants (transpiration)

Question 4

Water’s Properties: Solvent Properties (due to polarity) – Universal solvent

Answer 4

Dissolves and transports polar/ hydrophilic substances - nutrients (organic compounds/ inorganic ions) etc. around/ through organisms
Sap in plants (water up xylem and sugars down phloem)
Blood in animals (glucose, amino acids, fibrinogen, hydrogen carbonate ions etc.)
Note: hydrophobic substances (cholesterol, fats, oxygen) have special means of transport in living systems (lipoproteins in blood, haemoglobin etc.)
Medium for metabolic reactions

Question 5

Water is used in living systems to

Answer 5

MAKE AND BREAK chemical bonds

Question 6

Condensation

Answer 6

creating larger molecules by removing water

Question 7

Hydrolysis

Answer 7

hydro = water, lysis = “slice/dice;” breaking): water is added to break bonds/ break larger molecules into smaller pieces (ex: digestive processes)

Question 8

Cell theory

Answer 8

All living things made of cells
Cells = smallest fundamental unit of life
All cells arise from pre-existing cells

Question 9

Evidence for the cell theory

Answer 9

Microscopes allow visualization of cells
NOTHING smaller than a cell found to survive (on OWN) – if not made of cells
Sterilization prevents cell growth

Question 10

Exceptions to cell theory

Answer 10

Muscle cells because Muscle cells fuse to form fibres that may be very long Consequently, they have multiple nuclei despite being surrounded by a single, continuous plasma membrane.

Question 11

Basic functions of life

Answer 11

Reproduction, growth, respiration (energy/ nutrients), cells, homeostasis, excretion, response, metabolism

Question 12

Stem cells…

Answer 12

retain the capacity to divide and have the ability to differentiate along different pathways.

Question 13

One therapeutic use of stem cells

Answer 13

Stem cells harvested from embryos – destroys/ kills embryo! (OR placenta/ umbilical cord)
Exposed to biochemicals in lab to cause differentiation into desired cell type
Transferred to patients who need them (photoreceptor cells for Stargardt’s disease, blood cells for leukemia) – requires immunosuppression of patient first so do not reject/ monitoring for cancer following transfer

Question 14

Prokaryotic cell

Answer 14

Divide by binary fission (asexual reproduction)
Have organelles WITHOUT membranes around them
Mitochondria and Chloroplasts (Eukaryotic cells) thought to have originated from primitive prokaryotic cell that was engulfe

Question 15

Eukaryotic cells

Answer 15

Have MEMBRANE-BOUND organelles

Question 16

Compare Prokaryotic and Eukaryotic

Answer 16

Similarities: Both have DNA,Both have a cell membrane, Both have cytoplasm/ carry out all functions of life, Both contain ribosomes
Differences:
Prokaryote Eukaryote
DNA is naked (no proteins) DNA associated with proteins (histones)
DNA is circular DNA is linear
DNA in nucleoid DNA in nucleus
DNA does NOT contain introns DNA contains many introns
No membrane-bound organelles/ no mitochondria Membrane-bound organelles/ mitochondria
70S ribosomes 80S ribosomes
Smaller (size less than 10um) Larger (size more than 10um)

Question 17

Structure of Membrane

Answer 17

Phospholipids have hydrophilic heads (polar) and hydrophobic (nonpolar) tails
Hydrophilic heads attracted to water and hydrophobic tails repelled by water
Phospholipid bilayer forms with polar heads toward/ in contact with water on both sides of the membrane (cytoplasm and extracellular fluids) and tails away from water (in the center of the bilayer)
Hydrophobic interactions between tails and hydrophilic interactions between heads and water stabilizes membrane structure
Interactions of phospholipids allow membrane fluidity (breaking/ remaking of membrane in endo- and exocytosis

Question 18

Functions of Membrane Proteins

TRACIE

Answer 18

T- Transport
R- Receptors
A- Anchorage
C- Cell recognition or Identification
I- Intercellular connections
E- Enzymatic connection

Question 19

Type of Transport: Passive

Answer 19

Movement of particles from high (HYPERTONIC) to low (HYPOTONIC) concentration

Question 20

Different types of Passive transport

Answer 20

Diffusion, Osmosis, Facilitated Diffusion

Question 21

Diffusion:

Answer 21

small/ nonpolar molecules move through membrane from higher (hypertonic) to lower (hypotonic) concentration (nonspecific protein channels allow small, polar ions to diffuse

Question 22

Osmosis

Answer 22

diffusion of water molecules to balance solute concentrations

Question 23

Facilitated Diffusion

Answer 23

diffusion of large molecules through SPECIFIC protein channels (pores) in the membrane (proteins change shape to “facilitate” this movement)

Question 24

Type of Transport: Passive

Answer 24

Movement of particles from low to high concentration

Sodium/ Potassium Pump: maintains resting potential in nerve cells

Question 25

Cell Cycle

Answer 25

Interphase then Mitosis

Question 26

Interphase

Answer 26

G1 (growth, protein production, metabolic reactions etc.)
S (synthesis – DNA replication – copied chromosomes attached at centromere; copies called “sister chromatids”)
G2 (growth, protein production, duplicating organelles etc.)

Question 27

Mitosis

Answer 27

Prophase, Metaphase, Anaphase, and Telophase

Question 28

Prophase

Answer 28

nuclear membrane disappears, chromosomes condense and become visible, mitotic spindle forms

Question 29

Metaphase

Answer 29

chromosomes, as sister chromatids, line up individually (NOT as homologous pairs) along MIDDLE of cell

Question 30

Anaphase

Answer 30

centromeres split, sister chromatids separate; one copy of each chromosome pulled to opposite ends of cell by mitotic spindle fibers

Question 31

Telophase

Answer 31

nuclear membranes begin to reform and cytoplasm divides – cytokinesis – forming two IDENTICAL, diploid (2n = 2 copies of each chromosome) daughter cells

Question 32

Reasons a cell would divide

Answer 32

TOAD- Tissue repair, Organism Growth, Asexual reproduction, Development

Question 33

Cancer

Answer 33

uncontrolled cell division- do NOT respond to cell cycle controls–divide uncontrollably and produce masses of cells- Cancerous tissues have higher mitotic indexes as cells divide faster/ out of control

Question 34

Benign tumors

Answer 34

remain at original site or contained in membrane

Question 35

Malignant tumors

Answer 35

invading surrounding tissue

Question 36

Metastatic tumors

Answer 36

in blood; travel to other parts of body and form secondary tumors

Question 37

MItotic Index

Answer 37

# of cells in any stage of mitosis
         total # of all cells

Question 38

Water vs Methane

Answer 38

Water higher on everything