MDCAT online test Biology chapter wise Multiple choice questions(MCQs). Entry Test online preparation for free. MDCATustad is providing free online preparation of mdcat entry test. So avail this opportunity to achieve your goal.
MDCAT Online Test Biology Unit 1
Before you attempt the online quiz take a review of key points Biology chapter 1 cell structure and its functions.
- The oldest accurately dated life form is a microorganism, Eu-bacterium
Isolated which dated back 3500 million years.
- The resolving power of a light microscope is 250nm, which is about 500X
that of the naked eye.
- The human naked eye can differentiate between two points at least
- The magnification power of a light microscope is as much as 10,000 times.
- Transmission electron microscope Item) can magnify an object up to
1,000,000 (I million) times.
- For 3D images of whole objects, a scanning electron microscope is used.
- The process in which different types of stain (dyes or color) are applied to
cell or part of the cell to %differentiate” or examine easily is called staining.
- The first stain applied to a component is called a principle stain.
- Counter Stain, the stain that makes cell structure more visible, when
not completely visible with the principle stain.
- Example: crystal violet stains only Gram-positive bacteria in Gram
staining. Safranin a counter stain is applied that stains all cells, allowing identification of Gram -ve bacteria.
- Vital Stain: non-toxic stain applied to cell or tissue which do not harm
- Types; Supra vital and intravital stain.
- Vital stain applied to a cell or tissue removed from a body is called
- Vital stain applied to a cell or tissue which is still the part of a body is
called intravital stain. ‘
- The culture of cell or tissue, organ (in vitro) outside the living bodies in a
nutrient artificial medium in antiseptic conditions is called tissue culture.
- Tissue culture is done on liquid nutrient medium i.e BROTH and AGAR or
semi-liquid nutrient medium.
- IN VIVO: The process inside the living e.g in-vitro fertilization.
- IN VITRO: The process occurs outside the living.
- The meristematic tissues are used in tissue culture because they are
rapidly dividing tissue, so most commonly the ex-plant of meristematic
- Sterilization: The process treatment of ex-plant with the antiseptic
the chemical is called sterilization.
The following chemical is most commonly use;
- Root formation is done with high auxin, low cytokinin ratio.
- Shoot-formation is done with low auxin, high cytokinin ratio.
- Callus formation occurs with the same auxin to cytokinin ratio.
- Cell wall is ABSENT in animal cells.
- Present in plant cell composed of cellulose.
- Present in fungi cell composed of chitin.
‘ 27. Present in a bacterial cell composed of murine or peptidoglycan.
- Cell wall is the secretion of Golgi bodies
- It is freely permeable.
- Cell wall is composed of the following three layers:
a. Outer – Middle lamella (1µm)
b. Middle – Primary wall (I to 3 µm)
c. Inner – Secondary wall (5 to 10 µm)
- Plant cell without a cell-wall is called protoplast.
- Nucleus + cytoplasm is called protoplasm.
- Cell membrane also called cell surface membrane or plasma membrane
and is found in all prokaryotic and eukaryotic cells.
- it lies below the cell wall.
- Cell membrane is composed of 60-80% protein and 20-40% lipids.
- Proteins of the cell membrane are extrinsic protein, intrinsic protein and
transport protein or permease.
- Extrinsic protein: These proteins are found on the surface of the membrane.
- Intrinsic proteins: These protein extend completely through the double
membrane from one side to another.
- Transport protein or perm-ease: Many small molecules and non-polar
molecule pass through lipid while large and polar molecule cannot pass
through lipids, they must pass with the help of a protein called permease.
- Transport of substances across the cell membrane through protein is
called facilitated transport:
- Facilitated transport may be;
- The movement of substances from a region of low concentration to high
concentration with the help of energy is called active transport.
- The movement of substances from a region of high concentration to low
concentration without the help of energy is called passive transport. It
occurs through gates.
- Active transport must occur with the help of special proteins called
- Proteins make the membrane selectively permeable because it selects the
transport of substance according to the need of cell.
- Cytoplasm consists of; Soluble part (cytosol)
- Insoluble part (cell organelle e.g. mitochondria, E.R, plastid)
- the cytosol contains 90% H2o and small ions which together form true
- Glycolysis occurs in the cytosol.
SO. The membrane of the endoplasmic reticulum is called cristae.
There are two types of endoplasmic reticulum i.e SER & RER.
- Rough E.R has ribosomes attached to its surface.
- Smooth E.R has no ribosomes.
- Smooth E.R helps in;lipid synthesis (especially steroid hormone synthesis)
Detoxification of harmful drugs. Muscle contraction Transmission of in; pulse
Mechanical support. In muscle cell E.R is called the sarcoplasmic reticulum
- Ribosomes synthesized in the nucleolus in a eukaryote,
- In eukaryotes the ribosome is of larger size (the 80S) with a smaller sub unit of
The 40s and a larger sub unit of 60s