Nucleic Acids Summary

Nucleic Acids

• Nucleic acids are long-chain polymers composed of nucleotides that are the constituents of living organisms.
• They are named based on their chemical properties and the fact that they are the major component of the cell nucleus.
• DNA and RNA are the main types of nucleic acids.
• DNA is made up of purines (adenine and guanine) and pyrimidines (cytosine and thymine).
• Nucleic acids are macromolecules composed of several molecular units called nucleotides, which are linked to each other in the form of a chain.
• A base pair has two nucleotides bonded to each other, forming a ladder-like structure.
• A DNA molecule is comprised of two strands that twist around each other, forming a twisted ladder.
• Each strand has a backbone made up of deoxyribose sugar and phosphate groups, with each sugar molecule attached to one of the four nitrogen bases (adenine, guanine, thymine, and cytosine).
• The two strands are bonded together with the help of hydrogen bonds, with guanine and cytosine having three hydrogen bonds and adenine and thymine having two hydrogen bonds.
• The major functions of nucleic acids include the storage of genetic information and material used for the reproduction of the living cell.

Abiotic Synthesis

• Abiotic synthesis refers to the creation of organic molecules from non-life.
• Organic molecules are carbon-based compounds believed to be the building blocks of life.
• Examples of organic molecules include nucleic acids, carbohydrates, and proteins.
• Water is not considered an organic molecule.
• The Oparin-Haldane hypothesis proposes that life arose from gradually and by chance from gases in the early Earth's atmosphere.
• The Miller-Urey experiment demonstrated that organic molecules could be produced without cells, based on early Earth's atmospheric content.

Organisms

• An organism is a living system that can respond to stimuli, reproduce, grow, develop, adapt, and maintain homeostasis.
• Homeostasis is the process by which the systems within an organism work together to maintain a consistent internal environment or state of balance.
• All living things have the ability to respond to stimuli, reproduce, grow, develop, adapt, utilize a source of energy, and maintain homeostasis.
• The domain classification system divides all organisms into three domains: Bacteria, Archaea, and Eukarya.
• The Bacteria and Archaea domains include only unicellular organisms, while the Eukarya domain includes all multicellular living organisms and some unicellular protists.
• Multicellular organisms are structurally organized into cells, tissues, organs, and organ systems.
• Cells are the smallest unit of life, and every organism is composed of cells.
• Cells have organelles, which are membrane-bound structures that have a specific function.
• Examples of organelles in eukaryotic cells include the nucleus, vacuoles, and chloroplasts.

Animal Cells

• An animal cell is a eukaryotic cell present in all organisms of the animal kingdom.
• The shape of the cell varies and depends on the function performed by the cell.
• The animal cell structure is composed of the cell membrane, cytoplasm, and cell organelles.
• The nucleus is the control center of the cell and contains the cell's genetic material or DNA.
• Mitochondria are organelles that help the cell break down food and release energy.
• Ribosomes synthesize proteins and are either freely scattered within the cell or found associated with the endoplasmic reticulum.
• The Golgi body helps in the packaging and secretion of proteins received from the ER.

Cell Membrane

• The cell membrane, also known as the plasma membrane, is a thin, flexible barrier that separates the cell from the environment.
• The bulk of the cell membrane is made of phospholipids, which are arranged in a bilayer.
• Phospholipids are amphipathic and have hydrophobic tails and hydrophilic heads.
• The cell membrane also has additional components, including cholesterol, proteins, and carbohydrates.
• The cell membrane can be described by the fluid mosaic model, which states that the cell membrane is fluid and flexible and moves with the cell.

Homeostasis

• Homeostasis is the internal set of conditions that living things maintain in order to function at their best.
• Homeostasis is maintained through negative feedback loops, where the product of a process shuts the process off.
• Examples of homeostasis in living things include temperature regulation, water and salt balance, and glucose levels.
• Homeostasis is also regulated at the cellular level by the cell membrane, which maintains homeostasis in three main ways:
  • Allowing for fluid movement of the membrane
  • Regulating osmosis, or the movement of water from high concentration to low concentration
  • Maintaining specific concentrations of ions

Organelles

• The nucleus is the control center of the cell and contains the cell's genetic material or DNA.
• The endoplasmic reticulum (ER) is a collection of tube-like structures within the cytoplasm that acts as a highway transporting substances throughout the cell.
• ER can be either smooth or rough, with rough ER having ribosomes on its surface that make it bumpy.
• Ribosomes are small organelles that make proteins.
• Mitochondria are the powerhouses of the cell, where cellular respiration takes place.
• Lysosomes contain enzymes that help digest food and cell debris.
• The Golgi bodies are the packaging and distribution centers of the cell, packaging up proteins to be released out of the cell.

Energy and Mitochondria

• Energy is vital in all living organisms.
• Mitochondria are rod-shaped organelles that are double membrane-bound and located in the cytoplasm of the cells.
• Cellular respiration takes place in the mitochondria, and they are referred to as powerhouses in a cell.
• Mitochondria play a role in the oxidation of fuel molecules in the cell, leading to the production of ATP.
• Prokaryotic cells lack mitochondria and rely on the external environment for their energy requirements.

Nucleus

• The nucleus is the control center of the cell and contains the cell's genetic material or DNA.
• The nucleus is contained within the nuclear envelope, a membrane that protects the DNA.
• The envelope is peppered with nuclear pores that allow substances to enter and exit the nucleus.
• Inside the envelope is the nucleoplasm, a liquid that contains chromatin, or the structure formed from DNA and proteins.
• Also in the nucleoplasm is the nucleolus, which controls the production of ribosomes through the creation of rRNA.

Cytoskeleton

• The cytoskeleton is a network of protein fibers that form the structural network of the cell.
• The cytoskeleton's main function is structure and support for the cell, but it also plays a role in the following processes:
  • Supporting the cell membrane
  • Intracellular trafficking of organelles and vesicles
  • Separation of chromosomes during cell division
• There are two main parts of the cytoskeleton: protein fibers and motor proteins.
• Protein fibers are long strands that make up the structure of the cytoskeleton and include three types: microfilaments, intermediate filaments, and microtubules.
• Microfilaments are made of the protein actin and are important for cell motility and contraction.
• Intermediate filaments are used for structure and support and include examples like keratin.
• Microtubules are the largest components of the cytoskeleton, made of tubulin, and are primarily used for the transport of cellular materials.

Nucleic Acids

• Nucleic acids are long-chain polymers composed of nucleotides, a major component of the cell nucleus.
• DNA and RNA are the main types of nucleic acids.
• DNA is made up of purines (adenine and guanine) and pyrimidines (cytosine and thymine).
• A base pair has two nucleotides bonded to each other, forming a ladder-like structure.
• A DNA molecule consists of two strands that twist around each other, forming a twisted ladder.
• Each strand has a backbone made up of deoxyribose sugar and phosphate groups.
• Each sugar molecule is attached to one of the four nitrogen bases (adenine, guanine, thymine, and cytosine).
• The two strands are bonded together with the help of hydrogen bonds.
• Guanine and cytosine have three hydrogen bonds between them, and adenine and thymine have two hydrogen bonds between them.

Abiotic Synthesis

• Abiotic synthesis refers to the creation of organic molecules from non-life.
• Organic molecules are carbon-based compounds that are believed to be the building blocks of life.
• Examples of organic molecules include nucleic acids, carbohydrates, and proteins.
• The Oparin-Haldane hypothesis asserts that life arose from gradually and by chance from gases in the early Earth's atmosphere.
• The Miller-Urey experiment demonstrated that organic molecules could be produced without cells, based on projections of early Earth's atmospheric content.

Organisms

• An organism is a living system that can respond to stimuli, reproduce, grow, develop, adapt, and maintain homeostasis.
• Homeostasis is the process by which the systems within an organism work together to maintain a consistent internal environment or state of balance.
• Organisms can be single-celled or multicellular, and all share the characteristics of responding to stimuli, reproducing, growing, developing, adapting, utilizing energy, and maintaining homeostasis.
• The domain classification system divides all organisms into three domains: Bacteria, Archaea, and Eukarya.
• The Bacteria and Archaea domains include only unicellular organisms, while the Eukarya domain includes all multicellular living organisms and some unicellular protists.
• Cells are the smallest unit of life, and every organism is composed of cells.
• Cells of multicellular organisms vary in size, shape, function, and metabolic activity, and compartmentalize many essential processes.

Cell Structure

• An animal cell is a eukaryotic cell present in all organisms of the animal kingdom.
• The cell structure is composed of the cell membrane, cytoplasm, and cell organelles.
• Organelles are covered with a plasma membrane.
• The nucleus is the control center of the cell and contains the cell's genetic material or DNA.
• Mitochondria are organelles that help the cell break down food and release energy.
• Ribosomes synthesize proteins and are either freely scattered within the cell or found associated with the endoplasmic reticulum.
• The Golgi body helps in the packaging and secretion of proteins received from the ER.

Cell Membrane

• The cell membrane, also known as the plasma membrane, is a thin, flexible barrier that separates the cell from the environment.
• The bulk of the cell membrane is made of phospholipids, which are arranged in a bilayer.
• Phospholipids are amphipathic and have hydrophobic tails and hydrophilic heads.
• The cell membrane also has additional components, including cholesterol, proteins, and carbohydrates.
• The cell membrane can be described by the fluid mosaic model, which states that the cell membrane is fluid and flexible and moves with the cell.
• The cell membrane maintains homeostasis through negative feedback loops, allowing for fluid movement, regulating osmosis, and maintaining specific concentrations of ions.

Homeostasis

• Homeostasis is the internal set of conditions that living things maintain in order to function at their best.
• Examples of homeostasis in living things include temperature regulation, water and salt balance, and glucose levels.
• Homeostasis is regulated at the cellular level by the cell membrane.
• The cell membrane maintains homeostasis through fluid movement, osmosis regulation, and ion concentration maintenance.

Organelles

• The nucleus is the control center of the cell and contains the cell's genetic material or DNA.
• The endoplasmic reticulum (ER) is a collection of tube-like structures within the cytoplasm that acts as a highway transporting substances throughout the cell.
• ER can be either smooth or rough, with ribosomes on the surface of rough ER.
• Mitochondria are the powerhouses of the cell, responsible for cellular respiration.
• Lysosomes contain enzymes that help digest food and cell debris.
• The Golgi body packages and distributes proteins received from the ER.

Energy and Mitochondria

• Energy is vital in all living organisms.
• Mitochondria are rod-shaped organelles that are double membrane-bound and located in the cytoplasm of cells.
• Mitochondria play a role in the oxidation of fuel molecules, leading to the production of ATP.
• The outer membrane of mitochondria is usually smooth, while the inner membrane is folded.
• The inner compartment of mitochondria is referred to as the matrix, and it contains most of the mitochondrial proteins and enzymes used in the oxidation of fats and the Krebs cycle.

Nucleus

• The nucleus directs the function of the organelles.
• The nucleus contains and protects the cell's DNA, which contains genes that code for a cell's structure and function.
• The nucleus controls which genes are expressed, ultimately determining how a cell will differentiate.
• The nucleus is contained within the nuclear envelope, a membrane that protects the DNA.
• The envelope is peppered with nuclear pores that allow substances to enter and exit the nucleus.
• Inside the envelope is the nucleoplasm, a liquid that contains chromatin, or the structure formed from DNA and proteins.
• The nucleus also controls cell division, protein production, and gene expression.

Cytoskeleton

• The cytoskeleton is a network of protein fibers that form the structural network of the cell.
• The cytoskeleton's main function is structure and support for the cell, but it also plays a role in intracellular trafficking, cell division, and cell motility.
• There are two main parts of the cytoskeleton, including protein fibers and motor proteins.
• Protein fibers are long strands that make up the structure of the cytoskeleton and include three types: microfilaments, intermediate filaments, and microtubules.
• Microfilaments are made of the protein actin and are important for cell motility and contraction.
• Intermediate filaments are used for structure and support, and include examples like keratin, which makes up our nails and skin.
• Microtubules are the largest components of the cytoskeleton, are made of tubulin, and are primarily used for the transport of cellular materials.

Learn about nucleic acids, their composition, and types including DNA and RNA. Discover the role of nucleotides, purines, and pyrimidines in these macromolecules.