Grade 12 results are out. Where to check yours

Unit notes and practice questions

Grade 12 Agriculture unit 5: Introduction to tissue culture

Everything here is for unit 5 of the Grade 12 Agriculture textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.

Get it on Google Play
3
Cards
10
Practice questions on unit 5
94–103
The textbook pages for unit 5

What unit 5 covers

  1. 1.Introduction to tissue culture
  2. 2.Types of crops produced by tissue
  3. 3.Benefits of tissue culture
  4. 4.Introduction to genetic engineering
  5. 5.Application of genetic engineering in crop

Short notes for unit 5

The cards filed under this chapter on the Grade 12 Agriculture page. Open one at a time.

FeatureConventional BreedingGenetic Engineering
Gene transfer sourceClosely related species onlyAcross taxonomic boundaries
Gene precisionMillions of random gene crossesDirect transfer of one or few specific genes
Undesirable genesMay transfer unwanted genesTransfers only the trait of interest
Time requiredTakes a long timeShorter time to achieve results

When you use it

Use when comparing traditional plant breeding methods with modern recombinant DNA genetic engineering techniques.

Drafted from Grade 12 Agriculture, pages 97-105, then checked twice before it went up

CropBiotechnology MethodSpecific Application
AsparagusTissue cultureClonal propagation of high-yielding male plants
PotatoTissue cultureRapid multiplication of disease-free tubers
Golden RiceGenetic engineeringBeta-carotene accumulation converted into Vitamin A

When you use it

Use when recalling specific crop examples modified or propagated through tissue culture and genetic engineering.

Drafted from Grade 12 Agriculture, pages 97-105, then checked twice before it went up

When you use it

Use when identifying which plant growth regulator controls root or shoot regeneration in culture media.

Watch out

Auxins stimulate root development, whereas cytokinins stimulate shoot development. Do not reverse these two roles.

Drafted from Grade 12 Agriculture, pages 97-105, then checked twice before it went up

Practice questions on unit 5

10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.

Question 1

What is totipotency in plant cell and tissue culture?

  1. A.The capacity of a cell to develop into an organism by regeneration
  2. B.The ability of a plant to grow without water or light
  3. C.The method of removing the cell wall from a plant cell
  4. D.The transfer of genes between unrelated organisms
Show the answer and why

Answer: A The capacity of a cell to develop into an organism by regeneration

Why

Totipotency is the basis of plant tissue culture and is defined as the capacity of a cell to regenerate and develop into a complete organism.

Question 2

In plant tissue culture, which plant hormone is added to the medium to stimulate shoot development?

  1. A.Cytokinins
  2. B.Auxins
  3. C.Ethylene
  4. D.Beta-carotene
Show the answer and why

Answer: A Cytokinins

Why

In tissue culture, cytokinins are used to stimulate shoot development, whereas auxins are used to stimulate root development.

Question 3

What term is used for plant cells that have had their cell walls removed?

  1. A.Protoplasts
  2. B.Explants
  3. C.Clones
  4. D.Tubers
Show the answer and why

Answer: A Protoplasts

Why

Protoplasts are single plant cells without cell walls that can be cultured to generate new plants.

Question 4

According to the textbook, which two plants have seeds with very low chances of germinating naturally and benefit from tissue culture?

  1. A.Orchids and nepenthes
  2. B.Teff and wheat
  3. C.Coffee and tea
  4. D.Cucumber and banana
Show the answer and why

Answer: A Orchids and nepenthes

Why

The textbook specifically identifies orchids and nepenthes as examples of plants whose seeds have very low chances of germinating and growing under natural conditions.

Question 5

Why are male asparagus plants preferred commercially over female plants?

  1. A.Male plants give higher yields
  2. B.Male plants produce larger seeds
  3. C.Male plants resist all insect pests
  4. D.Male plants do not need soil nutrients
Show the answer and why

Answer: A Male plants give higher yields

Why

Asparagus is dioecious with unisexual flowers. Male plants are high yielders and are commercially preferred over female plants.

Question 6

What are disease-free potato tubers washed with to remove impurities before sprouting in tissue culture?

  1. A.Detergent and distilled water
  2. B.Alcohol and auxin solution
  3. C.Pesticide and cytokinin liquid
  4. D.Warm milk and tap water
Show the answer and why

Answer: A Detergent and distilled water

Why

In potato multiplication, the disease-free tubers are washed with both detergent and distilled water to remove impurities and allow clean sprouting.

Question 7

Which of the following is a major limitation of conventional plant breeding?

  1. A.It can only exchange genetic material between the same or closely related species
  2. B.It cannot produce any seeds or fruits
  3. C.It requires expensive laboratory glassware like autoclaves
  4. D.It allows direct transfer of single genes from any organism
Show the answer and why

Answer: A It can only exchange genetic material between the same or closely related species

Why

Conventional breeding is limited to exchanging genetic material between the same or very closely related species, unlike genetic engineering which transfers genes across species barriers.

Question 8

Scientists created Golden Rice by inserting genes from which combination of sources?

  1. A.Daffodils, pea, a bacterium, and a virus
  2. B.Maize, wheat, an alga, and a fungus
  3. C.Potato, carrot, a yeast, and a virus
  4. D.Citrus, eucalyptus, aloe, and a bacterium
Show the answer and why

Answer: A Daffodils, pea, a bacterium, and a virus

Why

Scientists inserted four genes from daffodils, pea, a bacterium, and a virus into rice to produce Golden Rice.

Question 9

A laboratory in Hawassa conducts plant tissue culture under aseptic conditions. What does this mean?

  1. A.The environment is free from disease-causing germs such as bacteria and viruses
  2. B.The room is completely vacuumed of all air and gases
  3. C.The plants are grown in natural field soil without containers
  4. D.The medium contains only solid rock and water
Show the answer and why

Answer: A The environment is free from disease-causing germs such as bacteria and viruses

Why

An aseptic condition means the complete absence of germs, such as bacteria, viruses, and other microorganisms that can cause disease.

Question 10

Golden Rice is engineered to accumulate beta-carotene. What does the animal body convert beta-carotene into when consumed?

  1. A.Vitamin A
  2. B.Vitamin C
  3. C.Auxin
  4. D.Protein
Show the answer and why

Answer: A Vitamin A

Why

Beta-carotene is converted into vitamin A when consumed by animals and humans, helping fight vitamin A deficiency.

The app holds 12 questions on this unit, marked as you go. These are the first 10.

The textbook pages for unit 5

Unit 5 runs from page 94 to page 103 of the Ministry of Education edition.

Ministry of Education edition, English, 302 pages

Download the PDF

All Grade 12 Agriculture short notes

Practise this unit in the app

Temari turns this chapter into timed practice and marks it as you go, with an AI tutor to explain anything that did not land.

Start free

Temari.et is also an Android app, free on Google Play.

Get it on Google PlayAbout the Temari app
Sign inCreate your account