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.