Here students can locate TS Inter 1st Year Botany Notes 9th Lesson Cell: The Unit of Life to prepare for their exam.
TS Inter 1st Year Botany Notes 9th Lesson Cell: The Unit of Life
→ Cell theory laid emphasis on the unity underlying in the diverse forms, i.e., the cellular organisation of all life forms
→ The physico chemical approach to study and understand living organisms is called ‘Reductionist biology’.
→ G.N. Ramachandran
- G.N. Ramachandran, an outstanding figure in the field of protein structure, was the founder of the Madras school of conformational analysis of biopolymers.
- His discovery of the triple helical structure of collagen published in Nature in 1954 and his analysis of the allowed conformations of proteins through the use of the ‘Ramachandran plot’ rank among the most outstanding contributions in structural biology.
→ Cell is the basic unit of life in all living organisms.
→ Cytology is the study of structure and functions of cell and cell organelles.
→ Cell theory was proposed by Schleiden and Schwann and later by Rudolf Virchow.
→ Cells that have membrane bound nuclei are called eukaryotic cells.
→ In prokarytic cells genetic material is basically naked, not enveloped by a nuclear membrane.
→ Plasma membrane or cell membrane is lipoproteinaceous. Unit membrane (Sandwitch model) and Fluid mosaic models explain the structure and properties of plasma membrane.
→ Part of protoplasm except nucleus is called cytoplasm. It exhibits active movements. It shows cytoskeleton formed of microtubules and microfilaments.
→ Plastids, mitochondria and ER are double membraned cell organelles. Lysosomes, dictyosomes, glyoxisomes and peroxisomes are single membraned. Ribosomes are amembranous.
→ Plastids are 2 types – Leucoplasts and Chromoplasts.
→ Chloroplasts are green plastids concerned with photosynthesis.
→ Mitochondria are also called ‘power houses of cell’. Cellular respiration occurs in these cell organelles.
→ Endoplasmic reticulum consists of tubules, vesicles and cisternae. It is concerned with protein and lipid synthesis. It is an intracellular transportation channel.
→ Ribosomes are nucleoprotein particles. They are sites of protein synthesis.
→ Golgi complex (dictyosomes) consist of cisternae, vacuoles and tubules. They help in synthesis of cell wall materials and formation of cell plate during cell division.
→ Lysosomes are single membrane bound organelles with enzymatic matrix. They help in intracellular digestion. They also cause autolysis of cell contents (suicidal bags of cells).
→ Peroxisomes are involved in photorespiration and oxidation of fatty acids. Glyoxysomes contain enzymes related to glyoxalate cycle.
→ Fluid filled sacs of cell having sap bound by tonoplast are called vacuoles. Vacuole acts as a ‘store house of cell’ or ‘repository of cell’. It helps in osmoregulatory processes of cell.
→ Nucleus Is dynamic centre of cell or cell brain. It plays an important role in heredity.
→ Chromosomes are composed of coils of DNA bound to basic proteins – histones.
→ Choromatids are vertical halves of a chromosome attached to each other attached at centromere.
→ Basing on the position of centromere chromosomes are 4 types – metacentric, submetacentric, acrocentric and telocentric.
→ Chromosomes are physical basis of heredity.