Anaerobic Respiration

This page explains the process of anaerobic respiration in animal and plant/yeast cells.

Anaerobic respiration occurs in the absence of oxygen and takes place in the cell's cytoplasm. The process differs between animal cells and plant/yeast cells:

In animal cells:

• Pyruvate molecules are converted into lactic acid

In yeast and plant cells:

• Pyruvate molecules are converted into ethanol and carbon dioxide

Definition: Anaerobic respiration is the process of breaking down glucose without oxygen to produce energy.

Highlight: Anaerobic respiration, also known as fermentation, produces only 2 ATP molecules, making it less efficient than aerobic respiration.

Example: Lactic acid production in muscles during intense exercise is an example of anaerobic respiration in animal cells.

Aerobic Respiration

This page details the two-step process of aerobic respiration in cells.

Aerobic respiration occurs in the presence of oxygen and involves two main steps:

Step 1 $in the cytoplasm$:

• Glucose breaks down into 2 pyruvate molecules
• This releases energy to produce 2 ATP molecules

Step 2 $in the mitochondria$:

• Pyruvate molecules enter the mitochondria
• Pyruvate and oxygen are broken down into carbon dioxide and water
• This releases large amounts of ATP molecules

Definition: Aerobic respiration is the process of breaking down glucose in the presence of oxygen to release energy.

Highlight: Cells with more mitochondria can produce more energy through aerobic respiration.

Example: Muscle cells have numerous mitochondria to meet their high energy demands during physical activity.

Respiration Overview

This page provides a general overview of cellular respiration and its importance.

Respiration is a crucial process that occurs in every cell of living organisms. It involves breaking down glucose to release energy, which is then used for various cellular processes.

Key points about respiration:

• It is a series of enzyme-controlled reactions
• Glucose is broken down to release energy
• Energy is used to produce ATP $adenosine triphosphate$
• ATP transfers chemical energy for various cell processes

Definition: Respiration is the process by which cells break down nutrients to release energy for cellular activities.

Highlight: ATP produced through respiration is used for active transport, cell division, and protein synthesis.

Example: During muscle contraction, ATP provides the energy needed for muscle fibers to slide past each other.

Genetic Engineering

This page explains the process of genetic engineering using the example of human insulin production.

Genetic engineering involves transferring genetic information $e.g., a gene$ from one cell to another. The process of producing human insulin for diabetes treatment is used as an example:

1. Identify and isolate the insulin gene from a human chromosome
2. Use enzymes to cut the gene out of the chromosome
3. Remove a plasmid from a bacterial cell and cut it open using enzymes
4. Insert the insulin gene into the plasmid and seal it with enzymes
5. Return the altered plasmid to a new bacterial cell
6. Allow the bacteria to reproduce, producing insulin
7. Collect the insulin produced by the bacteria

Definition: Genetic engineering is the process of manipulating an organism's genes to introduce desired traits.

Highlight: This technique allows for the production of human proteins, like insulin, using bacterial cells.

Example: Other examples of genetic engineering include creating pest-resistant crops and producing human growth hormone.

DNA Structure

This page describes the structure and function of DNA $Deoxyribonucleic Acid$.

Key points about DNA:

• Double-stranded helix structure
• Held together by complementary base pairs
• Four bases: adenine $A$, cytosine $C$, guanine $G$, and thymine $T$
• Base pairing rules: C always pairs with G, A always pairs with T
• The sequence of bases determines the amino acid sequence in proteins
• A gene is a section of DNA that codes for a specific protein

Definition: DNA $Deoxyribonucleic Acid$ is the molecule that carries genetic information in living organisms.

Highlight: The base sequence in DNA determines the amino acid sequence in proteins, which ultimately influences an organism's traits.

Example: The gene for eye color contains a specific DNA sequence that codes for proteins involved in pigment production.

Enzymes

This page explains the function and properties of enzymes in living cells.

Enzymes are biological catalysts that speed up cellular reactions without being changed in the process. Key points about enzymes include:

• The active site of an enzyme is complementary to its specific substrate
• Enzyme actions result in products
• Enzymes can catalyze breakdown $degradation$ or build-up $synthesis$ reactions
• Each enzyme has optimal conditions for activity
• Enzymes can be denatured by changes in temperature or pH, affecting their shape and function

Definition: An enzyme is a protein that acts as a biological catalyst, speeding up chemical reactions in living cells.

Highlight: The shape of an enzyme's active site is crucial for its function, as it must fit its specific substrate like a lock and key.

Example: The enzyme amylase breaks down starch into simpler sugars in the digestive system.

Protein Synthesis

This page outlines the process of protein synthesis in cells.

The process of making proteins involves several steps:

1. DNA in the nucleus contains the genetic code
2. Messenger RNA $mRNA$ carries a copy of the genetic code from DNA to a ribosome
3. At the ribosome, amino acids are joined together to form proteins

Definition: Protein synthesis is the process by which cells build proteins based on the genetic information in DNA.

Highlight: Ribosomes play a crucial role in protein synthesis by assembling amino acids in the correct order.

Example: The synthesis of insulin in pancreatic cells follows this process, with the insulin gene being transcribed to mRNA and then translated into the insulin protein at ribosomes.

Types of Proteins

This page describes different types of proteins and their functions in living organisms.

Proteins have various shapes and functions depending on their amino acid sequence. The main types of proteins include:

1. Structural proteins - form parts of cells, organisms, or materials $e.g., spider silk$
2. Enzymes - biological catalysts that speed up chemical reactions in cells
3. Hormones - chemical messengers in the body
4. Antibodies - chemicals produced by white blood cells to fight infections
5. Receptors - proteins on cell surfaces that bind to specific hormones

Definition: Proteins are large, complex molecules made up of amino acids that perform various functions in living organisms.

Highlight: The specific sequence of amino acids determines a protein's shape and function.

Example: Collagen is a structural protein that provides strength and support to skin, bones, and other tissues.

Active Transport

This page explains the process of active transport across cell membranes.

Active transport is the movement of molecules or ions against their concentration gradient, from an area of lower concentration to an area of higher concentration. Key points about active transport include:

• It requires energy $usually in the form of ATP$
• Membrane proteins are involved in moving molecules or ions
• It moves substances from lower to higher concentration

Definition: Active transport is the energy-dependent movement of molecules or ions across a cell membrane against their concentration gradient.

Highlight: Active transport is essential for maintaining proper concentrations of ions and molecules in cells.

Example: The sodium-potassium pump in nerve cells uses active transport to maintain the correct balance of sodium and potassium ions for nerve impulse transmission.

Diffusion

This page describes the process of diffusion in cells.

Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. Key points about diffusion include:

• It occurs along a concentration gradient
• No energy is required for diffusion to occur
• It is a passive process

Definition: Diffusion is the passive movement of molecules or ions from an area of high concentration to an area of low concentration.

Highlight: Diffusion is an important process for the movement of small molecules and gases in and out of cells.

Example: Oxygen diffuses from the lungs into the bloodstream and then into body tissues due to concentration differences.