Information regarding in depth structure and function of cell organelles. Basics of bacteria and virus. According to 2025 -2027 A level Biology
Cell
Basic structural and functional unit of all living things
Two Types of Cell
Prokaryotes and eukaryotes
Size of prokaryotic cell
1-5umin diameter, typically smaller than eukaryotic cells.
Size of animal cell
20um
Size of plant cell
40 um to 100 um in diameter, generally larger than animal cells.
Prokaryotic cells always have a cell wall made of ——————-.
peptidoglycan.
Prokaryotes and Eukaryotes divide by different mechanisms called
Eukaryotes by mitosis and prokaryotes by binary fission.
What is the organelle that all eukaryotes have but prokaryotes do not?
Nucleus and membrane-bound organelles Like Endoplasmic reticulum, Golgi body and mitochondria
What are the structures found in all Bacteria?
Cell membrane, cytoplasm, 70s ribosomes, and circular DNA
What the structures found in some bacteria but not all?
Pili or Fimbriae, flagella, plasmids, cell wall, and slim capsule
Cell wall of bacteria is made of——————.
Murein
Circular DNA
Double stranded DNA joined at ends to create a loop usually found in prokaryotes.
Plasmids
Small Circular DNA molecules which have genes for anti-biotic resistance
Pilli or Fimbriae
Help with attachment to surfaces and other cells. Also help in Reproduction.
Virus
Non cellular structure with a nucleic acid core
Viruses have a protein coat made of ————————.
Capsid which has subunits capsomeres.
Outer envelope of some viruses is made of?
Phospholipids
Liquid substance in a cell is called
Cytosol
Double membrane organelles
Nucleus, chloroplast, Mitochondria
Single membrane organelles
Sap Vacuole, Golgi Body, Endoplasmic reticulum
Substances leaving the nucleus from the nuclear pore
mRNA and Ribosomes
Substances entering Nucleus from Cytoplasm
Proteins to make:
1) Ribosomes
2)Nucleotides
3)ATP
4) Hormones like Thyroid Hormone T3.
Chromosomes
Contain DNA which is organized into functional units called genes that control the activity of the cell and inheritance
Site of protein synthesis
Ribosomes and Rough Endoplasmic Reticulum
Site of transcription and mRNA production
Nucleus
Site of ribosomal synthesis
Nucleolus (inside the nucleus)
Chromatin
DNA and its associated proteins
Size of cell wall, cell membrane and nucleus
2um,7nm,7um respectively
Endoplasmic Reticulum form —————— compartments called, ————-.
flattened, sacs
Rough endoplasmic reticulum has ——————- but Smooth Endoplasmic Reticulum does not.
Ribosomes.
70s Ribosomes are found in all prokaryotes and in ————————- and ————————- of eukariyotes.
Mitochondria and Chloroplast
Ribosomes made of two subunits called
large subunit and small subunit
Size of 70s and 80s ribosomes
18nm and 22nm respectively
Function of Rough endoplasmic Reticulum VS Function of Smooth endoplasmic reticulum
RER = Site of protein synthesis and protein modification
SER = site for lipid and cholesterol synthesis
Euchromatin
loosely packed form of DNA and transcriptionally active (lightly stained under microscope)
Heterochromatin
Tightly packed form of DNA Transcriptionally inactive. (Deeply stained under microscope.)
Golgi boby
Stack of flattened sacs.
Golgi body formed by?
Transportation vesicles from RER on cis face
Golgi Body broken down to form?
Secretory vesicles and lysosomes on trans face
4 major roles of Golgi Body
Hint: ( Mia Paid For the Frogs:))
1) Modification of proteins and lipids. (like addition of phosphate group)
2) Packaging molecules into vesicles for transport
3) Formation of secretory vesicles to transport protein out of cell
4) Formation of lysosomes
Which amino acid is removed in golgi body from newly formed proteins to make them functional?
The first amino acid …… methioene
Role of golgi body in plants
converts sugar into cell wall components
Size of golgi body
7nm each cisterna
Size of Lysosome
1um
Lysosomes are ———— membraned, ——————sacs containing ———————- enzymes that work in —————- conditions. Example of these is ———————— present in sperms.
single, spherical, hydrolytic, acidic, acrosomes.
In ———————-, lysosomes digest bacteria in a process known as———————-.
White blood cells, Phagocytosis
Site of synthesize of ATP
Mitochondria
Mitochondria divides by —————.
Binary fission
A mitochondria’s inner fold form finger like projections called ————— which project into interior solution called ——————.
cristae, matrix
outer membrane of mitochondria has transport protein called————.
Porin
inner membrane of mitochondria has more ——————- barrier
selective
where does respiration occur and what is supplied to the reaction?
matrix solution and inner cristae. Hydrogen electrons with help of enzymes supplied.
Energy is released by breaking ATP into ————- in a —————- reaction. This is then —————- in the mitochondria to form ATP during ———————.
ADP, hydrolysis, recycled, respiration
cell surface membrane has a ——————————— appearance
Trilaminar
Light Dependent reaction in chloroplast and its location
Light energy absorbed and water is used to synthesize ATP.
occurs in thylakoid
Light Independent reactions in chloroplast and location
ATP used to covert Co2 into glucose also called co2 fixation. occurs in Stroma.
Arrange in proper order lamella, grana, and thylakoid
Lamella- single membrane in chloroplast
Thylakoid- fold in membrane
Granna- stack of folds in membrane
Microtubules are made of a protein called —————-. which has two types —————- and ———— tubulin. These two join together to form a —————. These join together end to end to form a long —————————-. ———- of this line up to form a ring.
Tubulin, Alpha, Beta, dimer, protofilament, 13
microtubules are the ———————— transport system as vesicles and organelles can move along their surface.
intracellular
microtubules form —————- in cell division to separate chromosomes and—————.
spindle fibres, centrioles
Microtubules along with ——————- filament form the cells ————.
Actin, cytoskeleton
Centrioles are ————- from most plant cells
absent
A centriole has a ————- centre and is made of ———————————— of microtubules.
hollow, nine triplets
microtubules for spindle formation are assembled by ——————-.
centrosomes
centrioles found at the base of cilia and ——————- known as ———————— extend microtubules which is vital for locomotion.
flagella basal bodies
Middle lamella contains substances like ——————— that glue substances to glue cells together.
pectin
Role of sap vacuole
1) support through turgor pressure
2)Lysosomal activity (contains hydrolytic enzymes)
3)Store nutrients
4)Store waste material
5)contains pigments
6) contain latex or calcium oxalate to avoid herbivores
Axoneme
cylinder of microtubules arranged in 9+2 arrangement
Nine—————- of microtubules make wall of axoneme present in cilia and flagella. Each duplet is made of two microtubules A and B. Microtubule A has complete ——— protofilaments while B is in complete and has ————- protofilaments.
duplet, 13, 10
When centrifuged in what order do organelles sediment?
nuceus——Chloroplast———-Mitochondria———RER—-Plasma membrane—-Ribosomes