1. What is the definition for growth?
Irreversible increase in the size and dry mass of an organism.
2. Which two processes will happen in growing?
(1) cell division
(2) cell enlargement
3. What is the definition of development?
An irreversible change in the form of an organism and an increase in its complexity
4. Which process will happen in development?
differentiation
5. What is the definition of cell differentiation?
The process of a cell becoming specialized to perform a particular function.
6. What are the structures of a seed?
External: micropyle, hilum, seed coat
Internal: plumule, radicle, cotyledon
7. What are the functions of cotyledons?
(1) They contains food which are used by the plumule and radicle during seed germination.
(2) They protect the delicate plumule tip.
(3) The cotyledons will turns green after seed germination to carry out photosynthesis until new leaves are formed.
8. What are the conditions required in seed germination?
(1) water
(2) suitable temperature (different for different seeds)
(3) oxygen
9. What is the significance of water to seed germination?
(1) soften the seed coat
(2) activate the enzymes in the seed
(3) as reactant for hydrolysis of food
(4) as a medium for transportation of soluble food.
10. What is the significance of oxygen in seed germination?
To allow seeds to carry out aerobic respiration to provide energy for growth of the embryo.
11. Describe the process of seed germination
(1) The seed coat breaks,
(2) the radicles grows downwards and become roots,
(3) root hair grows out from the radicle to increase water and mineral absorption from the soil.
(4) The plumule grows upwards and becomes the shoot.
(5) The shoot elongates and lifts the cotyledons away from the soil.
(6) The curved shoots straightens.
(7) The cotyledons turn green to carry out photosynthesis.
(8) Young leaves develop from the shoot and start carrying out photosynthesis.
(9) The cotyledons fall off.
12. What tissue can growth and development only take place in a plant?
meristems
13. What are meristems?
undifferentiated cells
14. Which positions are meristems located in plants?
(1) apical meristems: tips of roots and shoots
- increase the length of the plant, known as primary growth
(2) lateral meristems: the periphery of stems and roots.
- increase the thickness of the plant, known as secondary growth
15. What are the structures of the root tip and their corresponding functions?
(1) root cap: protect the root tip (apical meristem)
(2) region of cell divison: consists of the apical meristem
(3) region of elongation: the cells elongates
(4) region of differentiation: the cells differentiate into different types of specialized tissues
16. What are the features of cells at the region of cell division?
(1) the volume of each cell is small
(2) the cell wall is thin
(3) the cell density is higher
(4) the vacuole is small or even no vacuole
(5) carrying out mitotic cell division
17. What are the features of cells at the region of cell elongation?
(1) the cell wall is still very thin and elastic
(2) as vacuole forms, the cell is elongated
18. What are the features of cells at the region of cell differentiation?
(1) The wall of the cell thickens and hardens.
(2) The cells are differentiated into different type of tissue (root hair cell, xylem, phloem)
19. Where does lateral growth occur at the stem and root?
cambium
20. What are the parameters for measuring growth?
(1) size
(2) fresh mass
(3) dry mass
21. What are the methods of measuring size?
(1) length
(2) height
(3) surface area
(4) volume
22. What are the advantages and disadvantages of using size to measuring growth?
Advantages:
(1) no need to kill the organism, can measure the growth continuously
(2) easy to measure and convenient
Disadvantages:
(1) limited to certain dimension, cannot truly represent growth of other dimension.
23. What are the advantages and disadvantages of using fresh mass to measure growth?
Advantages:
(1) organisms remains alive, growth can be measured continuously,
(2) easy to measure and convenient
Disadvantages:
(1) not very accurate since the amount of water in the organism, which is not related to growth, varies with different environmental conditions.
24. What are the advantages and disadvantages of using dry mass to measuring growth?
Advantages:
(1) accurate in measuring the amount of organic matter
Disadvantages:
(1) the organism is killed
(2) the method is more complicated and time consuming
25. What is the meaning of dry mass?
It is the mass measured with all water removed.
26. How can dry mass be measured?
(1) Put the organism in an oven at slightly about 100 degree Celsius,
(2) wait until a constant mass is obtained.
27. What is a growth curve?
It is a curve showing the size, mass or growth rate of an organism with time.
28. Describe the change in dry mass in the 3 stages of growth in annual plants.
(1) Stage 1: dry mass decreases
(2) Stage 2: dry mass increases with time
(3) Stage 3: dry mass decreases
29. What are the stages of growth of human (as measured in height)
(1) infancy: rapid growth
(2) childhood: slower growth
(3) adolescence: rapid growth
(4) adulthood: height remains steady
(5) old stage: negative growth, slight decrease in height
30. What is the difference in the growth rate between the two sexes?
At 11-13 years old, growth rate of girls is faster than that of boys.
31. What are the differences in the growth rates of different body parts?
The brain grows up at an earlier stage
The sex organs grow rapidly only when puberty is reached.