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This is the complete lecture note for CPS 304 Crop Genetics and Breeding. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Course code: CPS 304 Course title: Crop Genetics and Breeding Course credit load: 2 Units Series 1: Fundamentals of Cell Structure and Genetics Outline Part 1.1: Cell Structure and Components Sub-Part 1.1.1: Overview of plant cell structure Sub-Part 1.1.2: Functions of major cell organelles Sub-Part 1.1.3: Differences between plant and animal cells Part 1.2: Chromosomes and Genetic Material Sub-Part 1.2.1: Structure and organisation of chromosomes Sub-Part 1.2.2: Chromosome number and variations Sub-Part 1.2.3: Linkage and crossing over Part 1.3: Genes and Mutations Sub-Part 1.3.1: Concept of genes in populations Sub-Part 1.3.2: Types and causes of mutations Sub-Part 1.3.3: Role of mutations in crop genetics Part 1.4: Cell Division Processes Sub-Part 1.4.1: Mitosis and its significance Sub-Part 1.4.2: Meiosis and its role in inheritance Sub-Part 1.4.3: Comparison of mitosis and meiosis
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Introduction Cells are the basic units of life, and understanding their structure and genetic components is essential for anyone studying crop genetics and breeding. Just as a house cannot stand without its foundation, crops cannot thrive without the cellular and genetic processes that underpin their growth and reproduction. This Series will provide you with the fundamental knowledge needed to appreciate how cells, chromosomes, genes, and cell division form the basis of plant breeding and crop improvement. The aim of this Series is to introduce you to the essential concepts of cell biology and genetics, equipping you with the ability to explain cell structures, describe chromosomes and genetic material, analyse the role of genes and mutations, and evaluate the processes of mitosis and meiosis in inheritance. We shall commence this Series by exploring the structure and components of plant cells, highlighting the functions of organelles and the differences between plant and animal cells. Next, we will examine chromosomes and genetic material, focusing on their organisation, variations, and the processes of linkage and crossing over. Subsequently, we will consider genes and mutations, looking at their role in populations and their importance in crop genetics. Finally, we will wrap up by studying cell division processes, comparing mitosis and meiosis, and discussing their significance in inheritance and crop breeding. Series Learning Outcomes Upon completing this Series, you should be able to: SLO 1.1 define the structure and major components of plant cells, SLO 1.2 explain the functions of key cell organelles and distinguish between plant and animal cells, SLO 1.3 describe the organisation and structure of chromosomes, SLO 1.4 analyse variations in chromosome number and explain the processes of linkage and crossing over, SLO 1.5 explain the concept of genes in populations and identify different types of mutations, SLO 1.6 evaluate the role of mutations in crop genetics and breeding, SLO 1.7 demonstrate the stages of mitosis and explain its significance in growth and repair, SLO 1.8 illustrate the stages of meiosis and evaluate its role in inheritance, and
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS SLO 1.9 compare mitosis and meiosis, highlighting their differences and relevance to crop breeding. 1.1 Cell Structure and Components 1.1.1 Overview of plant cell structure A cell is the basic structural and functional unit of life. In plants, cells are enclosed by a rigid cell wall, which provides support and protection. Inside the cell wall lies the cell membrane, a thin layer that regulates the movement of substances in and out of the cell. The interior of the cell is filled with cytoplasm, a jelly-like substance that houses various organelles, each performing specialised functions. Fill in the blank: The jelly-like substance that houses organelles inside the cell is called __________.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.1 Structure of a typical plant cell 1.1.2 Functions of major cell organelles Each organelle within the plant cell has a specific role. The nucleus acts as the control centre, storing genetic material and directing cell activities. Mitochondria are the powerhouses, producing energy through respiration. Chloroplasts contain chlorophyll and are responsible for photosynthesis, enabling plants to produce food. Vacuoles store water, nutrients, and waste products, helping maintain cell shape. Other organelles such as the endoplasmic reticulum and Golgi apparatus are involved in protein and lipid synthesis, as well as packaging and transport. Fill in the blank: The organelle responsible for photosynthesis in plant cells is the __________.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Plate 1.1 Chloroplasts as the site of photosynthesis 1.1.3 Differences between plant and animal cells Although plant and animal cells share many similarities, there are distinct differences. Plant cells have a cell wall, which animal cells lack. They also contain chloroplasts for photosynthesis, whereas animal cells do not. Plant cells typically have a large central vacuole, while animal cells have smaller, scattered vacuoles. These differences reflect the unique roles of plants in producing food and maintaining ecological balance. Fill in the blank: Unlike animal cells, plant cells possess a rigid __________ that provides structural support. Feature Plant Cells Animal Cells Cell wall Present (rigid, made of cellulose) Absent Chloroplasts Present (site of photosynthesis) Absent Vacuoles Large central vacuole for storage and maintaining turgor pressure Small, temporary vacuoles (if present) Shape Generally rectangular or fixed due to cell wall Generally round, irregular, or flexible Energy storage Store energy as starch Store energy as glycogen Lysosomes Rare or absent (functions often carried out by vacuoles) Present and prominent
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Feature Plant Cells Animal Cells Centrioles Usually absent (except in lower plant forms) Present, play key role in cell division Mode of nutrition Autotrophic (produce food via photosynthesis) Heterotrophic (depend on external food sources) Table 1.1 Key differences between plant and animal cells Pilot questions 1.1 The jelly-like substance that houses organelles inside the cell is called __________. The organelle responsible for photosynthesis in plant cells is the __________. Name the organelle that acts as the control centre of the cell. Unlike animal cells, plant cells possess a rigid __________. State one difference between plant and animal vacuoles. 1.2 Chromosomes and Genetic Material 1.2.1 Structure and organisation of chromosomes Chromosomes are thread-like structures found in the nucleus that carry genetic information in the form of DNA. Each chromosome is made up of DNA tightly coiled around proteins called histones, which help maintain its shape and regulate gene activity. Chromosomes ensure that genetic material is accurately passed from one generation of cells to the next. Fill in the blank: The proteins around which DNA coils to form chromosomes are called __________.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.2 Structure and organisation of a chromosome 1.2.2 Chromosome number and variations The chromosome number refers to the specific number of chromosomes found in the cells of a species. For example, humans have 46 chromosomes, while many crop plants have different numbers depending on their species. Variations in chromosome number can occur due to processes such as polyploidy, where organisms have more than two sets of chromosomes. Polyploidy is common in plants and often leads to increased vigour and adaptability. Fill in the blank: The condition in which organisms have more than two sets of chromosomes is called __________.
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