General Biology and Human Physiology

Karyokinesis refers specifically to the division of the cell nucleus during mitosis. The term comes from Greek: "karyon" meaning nucleus and "kinesis" meaning movement/division. Chromosomes are the structures that divide, but the process itself is called karyokinesis.

Ribosomes are cellular organelles responsible for protein synthesis. They read messenger RNA (mRNA) and assemble amino acids into polypeptide chains according to the genetic code. Chloroplasts are for photosynthesis, chromosomes contain DNA, and cellulose is a structural polysaccharide in plant cell walls.

Apical meristem is the tissue at the tips of roots and stems where active cell division occurs, enabling growth in length. This region contains undifferentiated cells that can specialize into various plant tissues. Areolar tissue is loose connective tissue, antigens trigger immune responses, and axons are nerve fibers.

A gland is a specialized group of cells that produces and secretes chemical substances like hormones, enzymes, or sweat. Examples include sweat glands, endocrine glands, and exocrine glands. Elastin is a protein, coagulation is a process, and epidermis is a tissue layer.

Leucocytes (white blood cells) are the primary cells that help the body resist infections and foreign invaders. They are part of the immune system and include neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Erythrocytes are red blood cells that carry oxygen, while lymphocytes and monocytes are specific types of leucocytes.

Myofibrils are the rod-like contractile elements within muscle fibers, composed of overlapping thick (myosin) and thin (actin) filaments. These filaments slide past each other during muscle contraction. Neurons transmit nerve signals, mast cells are involved in immune response, and sarcolemma is the muscle cell membrane.

Adipose cells (adipocytes) are specialized for storing fat (triglycerides) in their large vacuoles. They serve as energy reserves and provide insulation. Mast cells mediate immune responses, fibroblasts produce collagen, and macrophages engulf pathogens.

Plasma is the clear, yellowish fluid portion of blood that remains after removing blood cells (corpuscles). It contains water, proteins, electrolytes, hormones, and clotting factors. Serum is similar but lacks clotting factors, lymph is a separate fluid, and vaccines are biological preparations.

A ligament is a flexible, dense fibrous connective tissue that connects bones to other bones or bones to cartilage. They provide stability and limit excessive movement at joints. Xylem transports water in plants, bone is hard tissue, and tendons connect muscle to bone.

A sprain is an injury caused by excessive stretching or tearing of ligaments, the tough bands of tissue connecting bones. Strains affect muscles/tendons, tension is force, and fracture is a break in bone. The term specifically refers to ligament damage.

The epidermis is the outermost layer of cells in multicellular organisms, serving as the protective barrier against environmental factors. It prevents water loss and protects against pathogens. Elastin is a protein, erythrocytes are red blood cells, and epithelium is a broader tissue category.

Collagen is the most abundant protein in the human body, making up about 30% of total protein content. It provides structural support to connective tissues like skin, bones, tendons, and ligaments. Haemoglobin is found only in red blood cells, keratin in hair and nails, and myoglobin in muscles.

Cytoplasm is the gel-like substance that fills the space between the plasma membrane and nuclear envelope. It contains organelles, cytosol, and various inclusions. Protoplasm refers to all living contents of the cell, chromosome is genetic material, and cellulose is a plant cell wall component.

The plasma membrane (also called cell membrane) is the outer boundary that separates the cell from its external environment. It controls what enters and exits the cell. Cytoplasm is inside the membrane, protoplasm includes all living contents, and nucleus is the central organelle.

Protoplasm is the living substance that makes up a cell, consisting of cytoplasm, nucleus, and other organelles. Cytoplasm is just the gel outside the nucleus, gene is a unit of heredity, and DNA is the genetic material within the nucleus.

Dehydration is the excessive loss of water from body tissues when fluid intake cannot replace fluid loss due to bleeding, diarrhea, vomiting, or excessive sweating. Rehydration is the process of restoring fluids, while retardation and deformation are unrelated to fluid loss.

Congenital diseases are those present from birth, which may be inherited or caused by factors during pregnancy. Contagious diseases spread from person to person, vector-borne diseases are transmitted by vectors like mosquitoes, and viral diseases are caused by viruses.

Proteins are the primary building materials for growth and repair of body tissues, making them essential macromolecules for building up the body. Sugars provide quick energy, mineral salts regulate various functions, and fats store energy and insulate organs.

Infectious diseases are caused by microorganisms including bacteria, viruses, fungi, and protozoa. These microscopic pathogens invade the body and multiply, causing disease. Unicellular and multicellular organisms are too broad categories, and 'micro organisms' is the specific term for disease-causing microbes.

A vector is an organism (like a mosquito) that transmits a disease from an infected person to a healthy person. Viral refers to viruses, scalar is a physics term unrelated to biology, and congenital means present from birth.

Vitamin D deficiency causes rickets in children, characterized by soft and weak bones due to impaired calcium and phosphorus absorption. Vitamin C deficiency causes scurvy, Vitamin A deficiency causes night blindness, and Vitamin B deficiencies cause various disorders like beriberi.

Vitamin D deficiency in adults causes osteomalacia, a condition of soft bones due to impaired bone mineralization. Osteoporosis is bone loss from aging, osteoblast is a bone-forming cell, and osteoma is a bone tumor. The adult equivalent of rickets is osteomalacia.

Atrophy is the decrease in size of a cell, tissue, or organ that was previously normal in size, often due to disuse, poor nutrition, or nerve damage. Anemia is a blood disorder, 'a deficiency disease' is too vague, and dehydration is fluid loss - neither describes shrinkage of developed structures.

Dendrites are the short, branched fibers of neurons that receive nerve impulses from other neurons or sensory receptors and conduct them toward the cell body. They increase the surface area for receiving signals from other neurons.