Structure of Cell Flashcards
If we study a cell under a microscope, we would come across three features in almost every cell: what are those?
All activities inside the cell and interactions of the cell with its environment are possible due to these features.
plasma membrane, nucleus and cytoplasm.
–Extremely delicate, thin , elastic, living and semi-permeable membrane
–Made up of two layers of lipid molecules in which protein molecules are floating
–Thickness varies from 75-110 A˚
–Can be observed under an electron microscope only
Plasma Membrane
Function of Plasma Membrane
Functions:
–Maintains shape & size of the cell
–Protects internal contents of the cell
–Regulates entry and exit of substances in and out of the cell
–Maintains homeostasis
–Non-living and outermost covering of a cell (plants & bacteria)
–Can be tough, rigid and sometimes flexible
–Made up of cellulose, hemicellulose and pectin
–May be thin or thick, multilayered structure
–Thickness varies from 50-1000 A˚
Cell wall
Function of Cell wall
Functions:
–Provides definite shape, strength & rigidity
–Prevents drying up(desiccation) of cells
–Helps in controlling cell expansion
–Protects cell from external pathogens
–Dense spherical body located near the centre of the cell
–Diameter varies from 10-25 µm
–Present in all the cells except red blood cells and sieve tube cells
–Well developed in plant and animal cells
–Undeveloped in bacteria and blue-green algae (cyanobacteria)
–Most of the cells are ________(having only one nucleus)
–Few types of cells have more than one nucleus (skeletal muscle cells)
- Nucleus
- uninucleated
Fill in the blank:
In nucleus…
1.) Nucleus has a double layered covering called _________.
2.) Nuclear membrane has pores of diameter about ________.
3.) Colourless dense sap present inside the nucleus known as ___________
4.) Nucleoplasm contains round shaped nucleolus and network of _________
5.) Fibres are composed of deoxyribonucleic acid (DNA) and protein histone
6.) These fibres condense to form chromosomes during ________
nuclear membrane
80-100 nm
nucleoplasm
chromatin fibres
cell division
Chromosomes contain stretches of DNA called ______
It transfer the _________ information from one generation to the next
genes, hereditary
Function of Nucleus
Functions:
1. Control all the cell activities like metabolism, protein synthesis, growth and cell division
2. Nucleolus synthesizes ribonucleic acid (RNA) to constitute ribosomes
3. Store hereditary information in genes
Answer what is being describe then fill in the blanks.
-Jelly-like material formed by _____ of water
-Present between the plasma membrane and the nucleus
-Contains a clear liquid portion called _____ and various particles
-Particles are proteins, carbohydrates, nucleic acids, lipids and inorganic ions
-Also contains many organelles with distinct structure and function
-Some of these organelles are visible only under an electron microscope
Granular and dense in animal cells and thin in plant cells
Cytoplasm:
80 %
cytosol
Network of tubular and vesicular structures which are interconnected with one another
Some parts are connected to the nuclear membrane, while others are connected to the cell membrane
Two types: smooth(lacks ribosomes) and rough(studded with ribosomes)
Endoplasmic Reticulum
Function of Endoplasmic Reticulum
Functions:
Gives internal support to the cytoplasm
RER synthesize secretory proteins and membrane proteins
SER synthesize lipids for cell membrane
In liver cells SER detoxify drugs & poisons
In muscle cells SER store calcium ions
Answer what is being describe then fill in the blanks.
Formed by stacks of 5-8 membranous sacs
Discovered by________
Sacs are usually flattened and are called the _______
Has two ends: ______ face situated near the endoplasmic reticulum and _______face situated near the cell membrane
Golgi body
Camillo Golgi
cisternae
cis, trans
Function of Golgi body
Functions:
Modifies, sorts and packs materials synthesized in the cell
Delivers synthesized materials to various targets inside the cell and outside the cell
Produces vacuoles and secretory vesicles
Forms plasma membrane and lysosomes
-Small, spherical, single membrane sac
-Found throughout the cytoplasm
-Filled with hydrolytic enzymes
-Occur in most animal cells and in few type of plant cells
Lysosomes
