Biology MDCAT Online Test MCQs Cell Structure and Functions Unit 1. Biology questions organised by chapter for the online MDCAT exam, including multiple choice answers (MCQs). Cost-free preparation available online for the Entry Test. Biology MDCAT Online Test, MDCATustad provides candidates with access to cost-free online preparation materials for the MDCAT entrance exam. Therefore, make the most of this opportunity to reach the goal you’ve set for yourself.
MDCAT Online Biology Test:
Before you attempt the online quiz take a review of key points Biology chapter 1 cell structure and its functions.
Key Points:
- 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
1.0mm apart. - 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.
Key Points:
- 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
supravital stain. - 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
tissue used. - Sterilization: The process treatment of ex-plant with the antiseptic
the chemical is called sterilization.
The following chemical is most commonly use;
Sodium hypochlorite
Calcium hypochlorite
Mercuric chloride
- 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)
Key Points:
- 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.
- Proteins of the cell membrane are extrinsic protein, intrinsic protein and
transport protein or permease. - 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
- The movement of substances from a region of high concentration to low
It
occurs through gates. - Active transport must occur with the help of special proteins called
pump. - 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
solution. - Glycolysis occurs in the cytosol.
SO.
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. - 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
Online Test Cell Structure & Functions:
Useful Resources For Entry Test Preparation
- Download STEP mdcat vocabulary Book
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