Untitled Flashcards Set

The Chemistry of Life

• Everything is made of chemical substances composed of atoms, and molecules form when atoms combine.

• Organic compounds always contain carbon and hydrogen, with many also containing oxygen, nitrogen, or phosphate.

• Carbohydrates, proteins, lipids, nucleic acids, and enzymes are all organic compounds with different functions.

Carbohydrates

• Carbohydrates contain hydrogen, carbon, and oxygen, providing energy to living organisms.

• Monosaccharides, like glucose, are simple sugars, tested with Benedict’s solution or Fehling’s solutions.

• Polysaccharides, large carbohydrate molecules, include starch for energy storage and cellulose in plant cell walls.

Lipids

• Lipids, including fats and oils, store energy and form cell structures; some, like phospholipids, contain phosphorus.

• Lipid molecules consist of three fatty acids joined to glycerol, releasing significant energy when broken down.

• Unsaturated fatty acids are mainly from plants and liquid at room temperature, while saturated fatty acids are mainly from animals and solid at room temperature.

Proteins and Enzymes

• Proteins, containing carbon, hydrogen, oxygen, and nitrogen, are vital for cell structure and function, including enzymes.

• Proteins are large molecules made of amino acids, sensitive to temperature and pH levels.

• Enzymes, biological catalysts, regulate chemical reactions in cells, with their activity dependent on temperature and pH.

Enzyme Function and Environmental Factors

• Enzymes have active sites that match substrate shapes, facilitating chemical reactions; they are not consumed in the process.

• Enzymes function optimally within specific temperature ranges; high temperatures can denature them.

• Every enzyme functions best at an optimum pH level; enzymes are used in biological washing powders and various industries.

Nucleic Acids and Vitamins

• Nucleic acids, found in all cells, control cell structure and function and are made of nucleotides.

• The two types of nucleic acids are ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).

• Vitamins, complex organic compounds in foods, are essential for health and metabolic processes.

Inorganic Compounds: Water and Minerals

• Water is the most important inorganic molecule, vital for cell mass and metabolic processes.

• Minerals are crucial for health and key chemical reactions, obtained from soil by plants and food by animals.

• Macro-elements are needed in large quantities, while micro-elements are needed in small quantities.

Animal Macro and Micro-Elements

• Calcium is found in dairy products and green vegetables, needed for teeth and bones; deficiency causes stunted growth and rickets.

• Iron, found in leafy vegetables, is needed for oxygen transport; deficiency leads to tiredness and anaemia.

Fertilizers and Cells

• Plants need inorganic nutrients for healthy growth, with fertilizers providing nitrogen, phosphorus, potassium, and other minerals.

• Overuse of fertilizers can damage soil and cause eutrophication, harming aquatic organisms.

• Cells, the basic units of life, consist of proteins, carbohydrates, lipids, nucleic acids, and water.

Cell Discovery and Theory

• Robert Hooke first identified cells in cork, and Antonie van Leeuwenhoek observed living cells.

• Schleiden and Schwann's findings led to the cell theory: all living things consist of cells, cells are the smallest living things, and all cells arise from pre-existing cells.

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Cell Structure and Organelles

• Cells are measured in micrometres and have a cell membrane, cytoplasm, and organelles.

• Cytoplasm is a fluid-like substance containing dissolved minerals, salts, gases, and organic substances.

• Organelles include mitochondria, chloroplasts, vacuoles, and nuclei, varying in number and type among cells.

Cell Membranes and Nucleus

• Cell membranes, made of phospholipids and proteins, control substance entry and exit.

• The cell membrane enables excretion and secretion by allowing waste products to leave the cell and substances to be secreted.

• The nucleus stores information and makes ribosomes.

Mitochondria and Endoplasmic Reticulum

• Mitochondria have inner and outer membranes; cellular respiration occurs inside, releasing energy.

• Endoplasmic reticulum consists of membranes forming channels; rough ER manufactures proteins, smooth ER manufactures lipids.

• Endoplasmic reticulum makes, stores and transports carbohydrates, lipids and proteins in the cell.

Ribosomes and Golgi Bodies

• Ribosomes, found in the cytoplasm, help make new proteins, either for the cytoplasm or for secretion.

• Golgi bodies process and package proteins and lipids from the endoplasmic reticulum into vesicles for distribution.

Animal Cell Organelles

• Animal cells have vesicles, vacuoles, and lysosomes.

• Lysosomes, formed from vesicles, contain enzymes to break down lipids and proteins, destroying foreign material and digesting food particles.

Plant Cell Organelles

• Plant cells have cell walls, plant vacuoles, and plastids.

• The cell wall, made of cellulose, provides shape, support, and protection.

• The vacuole in plant cells stores sugars, minerals and pigments in water.

Plastids and Cell Representation

• Plastids in plant cells include chloroplasts, chromoplasts, and leucoplasts.

• Chloroplasts contain chlorophyll, chromoplasts give colour to flowers and fruits, and leucoplasts store food.

• Cell membranes are selectively permeable, allowing certain substances to pass through based on size and chemical nature.

Movement Across Membranes

• Molecules move across membranes by diffusion, osmosis, or active transport.

• Osmosis is the movement of water from high to low concentration across a selectively permeable membrane.

• Active transport involves proteins carrying large molecules through the membrane, using energy.

Cell Division: Mitosis

• New cells are formed for growth and repair through cell division; errors in cell division can cause diseases like cancer.

• New cells are formed when existing cells divide. Two new cells are formed from each parent cell.

• The cell cycle includes cell growth, DNA replication, preparation for division, and karyokinesis/cytokinesis.

Interphase and Chromosomes

• Interphase involves cell growth, DNA replication, and preparation for division.

• Chromosomes contain information that controls all processes in the cell.

• During interphase, chromosomes form a chromatin network; before division, each chromosome copies itself into two chromatids joined by a centromere.

Mitosis Phases

• Mitosis consists of four phases: prophase, metaphase, anaphase, and telophase.

• Mitosis in plant cells lacks centrioles and forms a cell plate during telophase to separate daughter cells.

• Cytokinesis divides the cytoplasm to form two daughter cells; chromosomes elongate and reform into the chromatin network.

Mitosis Functions and Cancer

• Mitosis functions in organism growth, tissue repair, and asexual reproduction.

• Cancer is abnormal cell division caused by chemicals, radiation, viruses, diet, and lifestyle.

• Cancerous cells can spread to other parts of the body, forming malignant growths.

Cancer Treatment and Tissues

• Early cancer detection is crucial, using check-ups like Pap smears, colonoscopies, and mammograms.

• Cancer treatments include surgery, radiotherapy, chemotherapy, and traditional medicines.

• Tissues are groups of specialized cells, and organs are made of different tissues.

Plant Tissues

• Plant tissues include those for protection, storage, strength, transport, and growth.

• The epidermis, covering the plant surface, protects and prevents water loss with a waxy cuticle.

• Specialised epidermal cells allow gaseous exchange.

Epidermal and Parenchyma Tissues

• Guard cells, found in the epidermis, allow gases to enter and exit the leaf through stomata.

• Parenchyma tissue, made of unspecialised cells, acts as packing tissue and stores food and water.

• Chlorenchyma, a type of parenchyma, contains chloroplasts for photosynthesis.

Collenchyma and Sclerenchyma Tissues

• Collenchyma cell walls are thickened, providing strengthening ridges.

• Sclerenchyma cells have thick walls containing lignin and cellulose, providing strength and support.

• Sclerenchyma is made of fibres and stone cells.

Xylem and Phloem Tissues

• Xylem transports water and minerals from roots to the plant, with tracheids and vessels having thickened walls.

• Phloem transports food from leaves to other parts of the plant, consisting of sieve tubes and companion cells.

Meristematic Tissue

• Meristematic tissue, found at root and stem tips, is responsible for plant growth through cell division.

These cells differentiate and form various plant tissue types.