AP 8th Class Biology Notes Chapter 1 Cell Structure and Functions
→ Cell : The structural and functional unit of a living organism.
→ Cell MEMBRANE : The thin, flexible layer that surrounds a cell which controls all that enters and leaves the cell.
→ Cell WALL : The outer most non-living cellulose layer that surrounds the entire plant cell, including the cell membrane.
→ Chloroplast : It is the green coloured plastid, performs photosynthesis.
→ Chromosome : The thread like materials found in the nucleus. They contain genes.
→ Cytoplasm : The viscous fluid inside the cell which provides living nature to it.
→ Eukaryotes : The organisms with well developed nucleus are termed as eukaryotes.
→ Gene : The smallest units inheritance that are present on chromosomes.
→ Multicellular : Organisms having a large number of cells in their body.
→ Nuclear Membrane : Nucleus is separated from Cytoplasm by a membrane called nuclear membrane.
→ Nucleolus : A smaller spherical body in the nucleus.
→ Nucleus : It is the control centre of all cellular activities. It is spherical and located in the centre of the cell.
→ Organ : A group of tissues, specialized to perform a specific function.
→ Organelles : The smaller components or structures present in cell.
→ Plasma membrane : The membrane that is present around the cell.
→ Plastid : The coloured bodies found in the plant cells.
→ Prokaryotes : Cells having nuclear material without’nuclear membrane are termed as prokaryotes.
→ Pseudopodia : The projection emerging out of the body of amoeba, help in locomotion.
→ Tissue: A group of similar cells, performing a specific function.
→ Unicellular : Organisms like Bacteria and Amoeba contain only a single cell called unicellular organisms.
→ Vacuole : Blank looking structures in the cytoplasm is called vacuole.
→ White Blood Cell (Wbc): WBC are a part of blood cells that protects our body from pathogens. They can change their shape and engulf the pathogens with pseudopodia.
→ All living organisms are made of cells.
→ Cell is the structural and functional unit of all organisms.
→ Cells were first observed by Robert Hooke in 1665
→ Cells exhibit a variety of shapes and sizes.
→ Number of cells also varies from organism to organism.
→ The smallest cell is 0.1 to 0.5 micrometre in bacteria.
→ The longest cell measuring 170mm ×130 mm, is the egg of an Ostrich.
→ Organisms are divided into two groups i.e., unicellular and multicellular organisms. Unicellular organisms contain only one cell, performing all biological activities. Multicellular organisms contain a large number of cells.
→ The cell has 3 main parts. The cell membrane, cytoplasm and the nucleus.
→ Plant cells differ from those of animal cells in having an additional layer around the cell membrane, termed cell wall.
→ Cell wall gives strength and rigidity to plants.
→ The cells having nuclear material without nuclear membrane are called prokaryotic cells.
→ Cells having well-organised nucleus with a nuclear membrane are termed as eukaryotic cells.
→ Plant cells differ from animal cells is having cell wall, plastids and a big central vacuole.
→ Coloured bodies in plant cells are called plastids. Chloroplasts are green in colour and perform photosynthesis. They consist of a pigment called chlorophyll.