http://www.mhhe.com/biosci/pae/botany/stern8e/

 

LECTURE EXAM 2

 

¯    The Scientific Method and Experimental Design

¯    Metabolism

1.     Enzymes

2.    Cellular Respiration

3.    Photosynthesis

¯    Absortion and Transport

¯    Growth and Development

 

 

The Scientific Method and Experimental Design

1.     What is the reason for using an experimental cntrol?

2.     What does it mean to Òcontrol the variablesÓ in an experiment?

3.     What is a hypothesis? Give an example.

4.     Explain the difference between the independent and the dependent variable.

5.     Why is replication important?

6.     You should be able to identify the hypothesis, independent and dependent variables,  and constants and interpret experimental results for the experiments conducted during labs. You should also be able to discuss possible sources of experimental error.

 

Metabolism  Review Questions

7.     Define Òcatalyst.Ó

8.     What is an enzyme and what does it do?

9.     How does an enzyme control reaction rates?

10.  What is the relationship between a substrate and  the products?

11.  What two chemical compounds are very important  in transfering energy for cellular metabolism? (ie. they are like rechargeable batteries for cells)

12.  Describe how environmental factors such as temperature and pH infuence the rate of enzyme-mediated reactions.

13.  What other factors might affect the rate of enzyme-mediated reactions?

 

Respiration  Review Questions

1.     Define respiration.

2.     What is the reason cells respire?

3.     Why do plants respire?

4.     Why do we say that respiration is the reverse of  photosynthesis?

5.     Energy released from respiration comes from  ______, which is/are produced using energy from the sun.

6.     What are the products of respiration?

7.     Which has more energy to give off: ADP or ATP?

8.     Which has more energy to give off: NADP or  NADPH?

9.     In what organelle of the cell does aerobic  respiration occur?

10.  Where in the cell does anaerobic respiration  occur?

11.  The term Òaerobic respirationÓ means  that the process of respiration requires _______.

12.  Compare aerobic respiration and anaerobic  respiration.

13.  Which is more efficient?

14.  What is fermentation? Are  there different types?

15.  What is glycolysis and where in the cell does it  occur?

16.  What environmental factors affect respiration  rate in plants?

17.  What is digestion and what is its relationship to cellular respiration?

 

Photosynthesis Review Questions

1.     Define photosynthesis.

2.     What is necessary for photosynthesis to occur?

3.     What are the products of photosynthesis?

4.     In what organelle does photosynthesis occur?

5.     What are the thylakoids and stroma, where are  they located, what does each they do?

6.     What are the grana and stroma lamellae?

7.     Describe what occurs in each of the two parts of  photosynthesis.

8.     Why is one called the "light reaction"  and the other sometimes referred to as the "dark" reaction?

9.     What is the role of ADP and ATP and NADP and  NADPH in photosynthesis?

10.  Where does the oxygen given off in  photosynthesis originally come from?

11.  The "light" reaction is ________  dependent.

12.  The "dark" reaction is ________  dependent.

13.  What are the three types of photosynthesis?

14.  What types of plants use each type?

15.  What are the pros and cons of each?

 

Absorption & Transport Review Questions

1.     Plants need to absorb _____ and transport _____.

2.     Plants lose water through their __________.

3.     How do plants obtain water?

4.     What is transpiration?

5.     There are several factors by which water is moved  in the plant Ð what are they?

6.     How does an osmotic pump help move water in a  plant?

7.     Loss of turgor pressure causes plants to ______.

8.     What is capillary action?

9.     Capillary action occurs due to the fact that  water is both adhesive and cohesive. Explain how capillary action works to  distribute water in the plant.

10.  The smaller the volume of the cylinder, the  [greater? less?] the capillary force.

11.  How does soil moisture affect water availability for a plant?

12.  How does soil type affect water availability for a plant?

13.  What other factors determine water availability for a plant?

14.  Describe water flow into the roots.

15.  What causes stomates to open?

16.  What causes stomates to close?

17.  During what part of the day are plants most  water stressed? Least water stressed?

 

Growth & Development

1.     What is the difference between indeterminate and  determinate growth?

2.     What is morphogenesis?

3.     What are hormones and what do they do?

4.     What are the five major types of plant hormones  and what does each control?

5.     What is phototropism?

6.     What is gravitropism?

7.     What are phytochromes and what do they do?

8.     Discuss how plants respond to red and far-red  light.

9.     Describe how day length affects plant growth.

10.  What is totipotency?

11.   Explain: nastic movements, senescence, statoliths, thigmomorphogenesis, gravitropism, phototropism, turgor movements

 

 

 

 

SOME NOTES ON RESPIRATION

 

Complex food are digested into smaller compounds, which can then be respired

 

Respiration: the process of breaking down complex molecules resulting in the formation of CO2 + H2O and the release of usable energy

 

C6H12O6  + 6O2  ˆ     6 CO2    +     6H2O  + 686 kcal

sugar         + oxygen ˆ   carbon dioxide + water + energy

 

Plants fix solar energy from the sun during photosynthesis, but they require energy too, hence they also respire.

 

Plants require energy for:

  growth

  maintenance of tissue

  reproduction

  transport

  absorption , translocation, etc.

 

 

There are two types of respiration: Aerobic and Anaerobic

 

  aerobic respiration requires oxygen

 

  when a 6-carbon molecule of sugar is respired the  first stage of aerobic respiration (glycolysis) is the splitting of a  sugar molecule

[ÒglycoÓ = sugar,  ÒlysisÓ = to cut]

 

Respiration requires energy, but also results in the release of energy when chemical bonds are broken. Respiration results in a net gain in usable energy.

 

Respiration can occur in the absence of oxygen. This type of respiration is called Òanaerobic respiration.Ó

 

Fermentation is a type of anaerobic respiration.

 

In fermentation, alcohol replaces water as a product, hence the two products of anaerobic respiration are CO2 and alcohol.

 

 

What environmental factors affect respiration rate in plants?

 

  water availability

  temperature

  pH

  oxygen (for aerobic respiration)

 

Aerobic respiration is always more metabolically efficient than anaerobic respiration

(that is, the ratio of energy released to energy consumed is greater).

 

 

SOME NOTES ON GROWTH AND DEVELOPMENT

 

Plant growth and development are influenced both by heredity (genes) and environment.

 

Development includes growth (cell division and enlargement) and differentiation (formation of specialized tissues and stages of growth).

 

morphogenesis: developmental changes that lead to specific shapes

 

differentiation: functional specialization of plant cells (genetically determined)

 

determinate growth: growth having defined limits

 

indeterminate growth: growth does not have a predefined end point but instead continues unless stopped by an environmental of internal signal

 

totipotency: a cell which has the ability to make all other cells through division and growth and differentitiation vs. cells which have a limited number of ways in which they can develop; plant cells are often able to regain totipotency

 

 

differentiation is genetically determined and the coordination of development is carried out in response to a series of signals

 

signals are generally hormonal, but also may be from other sources such as environmental stimuli

 

hormone receptors consist of proteins that receive the signals and respond accordingly  (some substances are considered growth regulators rather than hormones, depending on how strict the definition of  hormones)

 

 

 

important plant hormones/growth regulators include

 

Plant  Hormone/Function/Used  in Agriculture to

 

auxin(indoleacetic  acid)/ promotes  cell wall expansion, stimulates cell division and growth, causes  apical dominance/ suppress  weed growth, stimulate root growth in rose cuttings, delay fruit and leaf drop

 

gibberellins/ promotes  cell divisiona nd elongation, stimulates  internodal growth, controls elongation, causes  bolting in plants with rosetts, stimulates  seed germination and end of dormancy/ stimulate  seed germination in many species; promote growth of reproductive and other  structures in some plants

 

abscissic  acid/ promotes  dormancy, triggers  leaf abscission. may  maintain seed dormancy. involved  in closing stomata under water stress

 

cytokinin/ coordinates  root and shoot growth, works  with auxin, delays  senescence/ apple  fruit growth and shape, tissue culture propagation

 

ethylene/ inhibits  growth and stimulates senescence, (also  involved in leaf abscission),  causes  fruit ripening/ influence  flowering and fruit ripening (apples  in bags)

 

 

phototropism: growth toward light

 gravitropism: growth away from gravity

 

both controlled by hormones which control growth

 

other hormones are being discovered

 

 

LIGHT & PLANT DEVELOPMENT

 

red-far-red response - germination, etiolation

 

phytochromes: protein molecules containing a pigment capable of absorbing red light; control the red-far-red response; may be more than one type of phytochromes

 

adaptive advantages: _________________________________

 

 

photoperiodic responses

 

photoperiodism: how plants "measure" day length

 

long-day plants

short-day plants

day-neutral plants

 

flower in response to length of uninterrupted night

(pointsettias)

 

hormones are involved in functioning of the biological clock of plants