Lab module 3

What are the main events of the cell cycle?

Interphase, mitosis, cytokinesis

What are the three phases of interphase?

G1 (first gap phase)

S (synthesis)

G2 (second gap phase)

G1

cells are growing in size and producing organelles

S phase

DNA is duplicated and two new DNA molecules are produced

G2

The cell continues to undergo growth

Define mitosis

the division of genetic information to create two identical nuclei

What are the four phases of mitosis?

Prophase

Metaphase

Anaphase

Telophase

prophase

chromatin condenses into chromosomes

nucleolus disappears and nuclear envelope disassembles

mitotic apparatus appears

mitotic apparatus

two asters, centrioles, spindle fibers (microtubules)

metaphase

chromosomes align at the metaphase plate

anaphase

the chromatids separate at the centromere and the daughter chromosomes are pulled to opposite poles of the cell

kinetochore

region of centromere that spindle fibers attach to in order to separate the chromosomes

daughter chromatids

identical chromosomes attached together by centromere

telophase

when the daughter chromosomes reach the poles, they unwind into chromatin, the nucleolus reappears, and the nuclear envelope reforms.

Cytokinesis

splitting of the cells cytoplasm into two parts

chromatin

non condensed DNA (looks like strands)

Cleavage furrow

Where the plasma membrane constricts during cytokinesis

Diffusion

the movement of particles from high concentration to low concentration

kinetic energy

energy in motion

brownian motion

random movement of particles

How do solutes move by diffusion?

kinetic energy. The particles in high concentration collide with other molecules causing them to disperse

Role of kinetic energy in diffusion

spontaneous motion of molecules (kinetic energy) causes collides which drives diffusion

role of concentration gradient in diffusion

difference between the two concentrations —> particles will move from high to low

role of temperature in diffusion

increases the rate of diffusion

higher temperature means more movement (kinetic energy) ➡ more random collisions ➡ molecules disperse faster

Relationship between molecular weight and rate of diffusion

lighter molecules will travel faster

Osmosis

water moves across a selectively permeable membrane from areas of low solute concentration (more water) to areas of high solute concentration (less water)

selectively permeable membrane

allows only certain particles to pass through

role of solutes in osmosis

osmosis measures the movement of water rather than the movement of solutes. more solutes = less water

equilibrium

two solutions have the same amount of solutes so there is no net movement

osmotic pressure

the amount of pressure needed to reach equilibrium (stop osmosis)

hypertonic solution

the solution has a greater concentration of solutes (less water)

what happens to a red blood cell in a hypertonic solution?

The red blood cell with crenate because water will rush OUT of the cell.

hypotonic solution

the solution has less solutes (more water)

what happens to a red blood cell in a hypotonic solution?

the RBC will swell and burst (lyse) because water rushed INTO the cell

isotonic solution

the solution has the same amount of solutes

what happens to a deshelled egg when you place it in hypertonic, hypotonic, and isotonic solutions?

hypertonic: water rushes out of the egg. Decrease in size

hypotonic: water rushes into the egg. Increase in size

isotonic: net movement of water. Size remains the same

filtration

separating solid particles from a liquid using a membrane

explain the importance of hydrostatic pressure in filtration

hydrostatic pressure is the physical force of a fluid against a membrane that moves the water and small solutes

hydrostatic pressure

fluid pressure on a membrane

effect of particle size on filtration

large particles cannot be forced through the membrane

explain filtration in the kidneys

allows removal of waste from blood into the kidneys.

hydrostatic pressure from the blood pushes small particles through gaps between cells, while large particles (such as proteins) remain in the blood

difference between diffusion, osmosis, and filtration

Diffusion focuses on movement of solutes, while osmosis focuses on the movement of water. Filtration uses physical pressure to drive particles through a membrane

*they are all passive transport but filtration uses physical pressure while the other two do not!

interphase

early prophase

late prophase

metaphase

early anaphase

late anaphase

telophase and cytokinesis

two daughter cells

does potassium permanganate or methylene blue travel faster?

potassium permanganate because it has a lower molecular weight

centromere

center of chromosomes. holds the sister chromatids together