Genetic Engineering

This page introduces the concept of genetic engineering, which is the artificial transfer of genes from one organism to another. This topic is often covered in National 5 Biology Unit 2 summary notes.

Definition: Genetic Engineering - The process of artificially transferring genes from one organism to another to modify traits or introduce new characteristics.

The page outlines the stages of genetic engineering:

1. Identify the required gene section in the source DNA.
2. Extract the required gene using enzymes.
3. Extract a plasmid from a bacterial cell.
4. Cut open the plasmid using enzymes.
5. Insert and seal the required gene into the bacterial plasmid using an enzyme.

Example: Applications of genetic engineering in food production include:

• Golden Rice (enhanced with Beta Carotene)
• Blight-resistant potatoes
• Longer shelf-life tomatoes

Highlight: Genetic engineering is used to improve crops' nutritional quality, disease resistance, and shelf life.

The page emphasizes that these modified crops are examples of genetically modified organisms (GMOs), which is an important concept in modern biology and often featured in Nat 5 Biology past papers.

Fermentation

This page covers the process of fermentation, which occurs in the absence of oxygen. Understanding fermentation is crucial for National 5 Biology Unit 3 Summary Notes.

Definition: Fermentation - A process that takes place when there is no oxygen present, allowing organisms to produce some energy from glucose.

The page compares fermentation in animal and plant cells:

1. In animal cells:

   • Glucose is broken down into pyruvate and then lactate.
   • This process occurs in the cytoplasm.

2. In plant cells (and yeast):

   • Glucose is broken down into pyruvate, which is then converted to ethanol and carbon dioxide.
   • This also occurs in the cytoplasm.

Highlight: Fermentation produces less energy (2 ATP) compared to aerobic respiration, but it allows for some energy production in anaerobic conditions.

The page also introduces the concept of a respirometer, used to measure the rate of respiration:

Example: In a respirometer, as a simple organism respires, oxygen is used up, causing the liquid in the tube to move as the volume decreases.

This information is particularly relevant for questions related to cell membrane function in national 5 biology pdf and cellular respiration processes.

Cell Structure and Function

This page provides an overview of the structures found in different types of cells, including plant, animal, fungal, and bacterial cells. It highlights the key components and their functions within each cell type.

Vocabulary: Cytoplasm - The gel-like substance within a cell where chemical reactions occur.

Definition: Cell membrane - A selectively permeable barrier that controls the entry and exit of substances in and out of the cell.

The page illustrates the various organelles present in different cell types:

• Plant cells: Cell wall, nucleus, cytoplasm, mitochondria, ribosomes, chloroplasts, vacuole, and cell membrane
• Animal cells: Nucleus, cytoplasm, mitochondria, ribosomes, and cell membrane
• Fungal cells: Cell wall, nucleus, cytoplasm, mitochondria, ribosomes, and cell membrane
• Bacterial cells: Cell wall, cell membrane, cytoplasm, ribosomes, and genetic material (including plasmids)

Highlight: The presence of a cell wall in plant, fungal, and bacterial cells, but not in animal cells, is a key distinguishing feature.

Each organelle's function is briefly described, such as the nucleus being the site of DNA and controlling cell activities, mitochondria as the site of aerobic respiration, and chloroplasts as the location for photosynthesis in plant cells.