Cell And Nucleus(chap1) Flashcards
Why is there a very little variation in cellular architecture of different species
Because all organisms originated from a single unicellular organism
Total number of cell present in the human body
75 trillion cells
What is responsible for the activities that happens between extra cellular compartments and intracellular compartments
Cell membrane
The components of cell ( in terms of organic and inorganic components) and the percentage of each in the mass of a cell
- Water : 70-75%
- Electrolytes
- Lipid : 2%
- Carbohydrates : 1%
- Protein : 10-20%
What does water helps in cellular function
In the transport of substances from one part to another
Chemical reaction occurring in cell take place in solution of water
What are the major electrolytes and which ones are mainly inside and outside the cell
. Potassium, magnesium and phosphate are mainly present inside the cell
. Sodium and chloride are mainly present outside the cell
. Calcium, sulphate and bicarbonate are also part of the major electrolytes of the cell
Main function of electrolytes
Regulation of water balance
Contraction and relaxation of muscle
Transmission of nerve impulses
In short it helps in cellular control mechanisms.
Types of protein (in terms of structure)
Globular protein
Structural protein
Features of globular proteins
. Globular or shaped like a ball in structure
. Made of individual protein molecules
. Found in mainly enzymes that catalyse various chemical reactions
What is the basic structural and functional unit of all living organisms?
Cell
Which organelle is known as the powerhouse of the cell?
Mitochondria
Which organelle is responsible for protein synthesis?
Ribosomes
What is the function of the endoplasmic reticulum (ER) in a cell?
Involved in protein and lipid synthesis
What is the function of the chloroplast in a plant cell?
Site of photosynthesis, where sunlight is converted into energy
Which organelle is involved in intracellular digestion and recycling of cellular components?
Vacuole
What is the function of the cell membrane in a cell?
Regulates the movement of substances into and out of the cell
Which organelle is involved in maintaining cell turgidity and storing water in plant cells?
Central vacuole
Which organelle is responsible for maintaining cell shape and movement in animal cells?
Cytoskeleton
What is the function of the nuclear membrane in a cell?
Surrounds the nucleus and controls the flow of molecules in and out
Which organelle is responsible for converting sunlight into energy in plant cells?
Chloroplasts
What is the function of the flagella in a cell?
Helps in cell movement
What is the function of the cilia in a cell?
Helps in attachment of cells and moving substances along the cell surface
What is structural proteins do
. Polymer of proteins molecules
. Long filament form
.provide contractile mechanisms for muscle
. Cytoskeleton of cilia axon
Found in collagen and elastic fibre
Short note on each water, electrolytes, proteins, lipid and carbohydrates
Page no. 4 and 5
What are major parts of cell
Nucleus
Cytoplasm
Cell membrane
What is the thickness of cell membrane
7-10nm
Composition of cell membrane
Protein: 55%
Phospholipids: 25%
Cholesterol: 13%
Other lipid: 4%
Carbohydrates: 3%
Which model of the cell membrane is most accepted
The fluid mosaics model purposed by singer and nicolson is the most accepted
What are the two main lipid in the cell membrane and what r its hydrophobic and hydrophilic parts
1.Phospholipid:
phosphate- hydrophilic part
Fatty acid- hydrophobic
2. Cholesterol:
Hydroxyl- hydrophilic
Steroid nucleus- hydrophobic
What r the position of the hydrophobic and hydrophilic parts of the cell membrane and which substances are permeable
. Hydrophobic lies towards the centre of the cell membrane
. Hydrophilic faces towards the surrounding water
. Water soluble substances such as ions and glucose are impermeable while lipid soluble substances such as alcohol and oxygen are permeable
Function of lipid
. Forms the cell membrane
. Selectively permeability as fat soluble substances are permeable while water soluble substances r not
. Provides framework for the attachment of proteins and carbohydrates
What are the two types of proteins present in cell membrane
Integral proteins: passes through the entire thickness of membrane and closely associated with the membrane lipid
Peripheral proteins: attached only to the surface and help in maintaining the cell shape and motility
Function of proteins
.Provide framework to cell
.helps in maintaining shape as well as motility of cell
.acts pump which helps in active transport
.acts as enzymes, receptors and ion channels
.also acts as carriers for facilitated diffusion
What is the thin layer of carbohydrates molecules through out of the surface of cell membrane called
Glycocalyx
Function of carbohydrates in cell membrane
Attached to other cell membrane’s glycocalyx
.act as receptors for binding hormones
. Participate in immune reaction
What is the central of the cell and what does it do
Nucleus
Controls the chemical reaction occurring in the cell and cell reproduction
What are the main part of nucleus are and what are composition of nucleus in dry weight
Main parts are nucleolus and chromatin material
In dry weight:
80% protein
18% DNA
2% RNA
What is chromatin
The nucleus contain densely staining network of dna and proteins which during cell division is identified as chromosome
What is the unit of heredity and how many chromosome are present in human
Gene r the unit of heredity and humans have 23pair of chromosome
Short note on nuclear membrane
The nuclear membrane has a outer and inner nuclear membrane. The outer membrane is continuous with endoplasmic reticulum (ER). The membrane contains thousands of nucleus pores which is 9nm in diameter as it allows only small weights molecules to pass through
Short note on nucleoli
Nucleoli is the lightly stained structure stored in the nucleus. They synthesise and store rna and protein molecules which later on transporting forms mature ribosome
Nucleoli: plural
Nucleolus: singular
What is cytoplasm and does it contain
The entire region between the cell membrane and nucleus. It contains
. Cytosol
.cell organelles
.cytoskeleton
.inclusion bodies
What is cytosol
It is the fluid portion in cytoplasm where cell organelles are present
Which cell contains multiple nucleus and which contains none
Multiple : skeletal muscle
None: matured RBCs
Structure of nucleus
Usually a nucleus is spherical in shape and is located near the centre of the cell. The nucleus covered with the nucleus envelope and the enclosed space is called as nucleoplasm in which nucleolus is present
The nucleolus is an organised structure of RNA, DNA and proteins that synthesis ribosomal RNA.
The remaining DNA is dispersed across the nucleoplasm called the chromatin fibre which during mitosis turns into a discrete structure called chromosomes
