Cell and Molecular Biology Fundamentals
Covers DNA replication, gene regulation (operons), cellular organelles, and basic tissue types (epithelial, connective, muscular, nervous)
Questions
If the gene encoding the trp repressor is mutated, such that it can no longer bind tryptophan, then will the transcription of the trp operon occur?
- Yes, because the trp repressor can only bind the trp operon and block transcriptional initiation when it is bound to tryptophan.
- No, because this mutation does not affect the part of the repressor that can bind the operator.
- No, because the trp operon is repressed only when tryptophan levels are high.
- Yes, because the trp operon can allosterically regulate the enzymes needed to synthesize the amino acid tryptophan.
The primary function of DNA polymerase is to
- add nucleotides to the growing daughter strand
- seal nicks along the sugar-phosphate backbone of the daughter strand
- unwind the parent DNA double helix
- prevent reassociation of the denatured present DNA strands.
DNA fingerprinting refers to
- molecular analysis of profiles of DNA samples
- analysis of DNA samples using imprinting devices
- techniques used for molecular analysis of different specimens of DNA
- techniques used for identification of fingerprints of individuals
Prokaryotic cell does not have
- Nucleolus
- Membrane bound organelles
- Controls
- All of these
Plasma membrane is
- Selectively permeable
- Permeable
- Impermeable
- Semi-permeable
Cell wall is present in
- Plant cell
- Prokaryotic
- Algal cell
- All of these
Cell wall of prokaryotes is made up of:
- Chitin
- Cellulose
- Glucose amine
- Mucopeptide
The endoplasmic reticulum is present in -
- Nucleus
- Chromosomes
- Nucleolus
- Cytoplasm
Which of the following is related to glycosylation of protein?
- Endoplasmic Reticulum
- Peroxisome
- Lysosome
- Mitochondria
Three morphological forms of golgi complex are
- Lamellae, tubules and vesicles
- Cisternae, tubules and vesicles
- Cisternae, tubules and lamellae
- Granum, thylakoids and vesicles
Golgi body is concerned with
- Respiration
- Secretion
- Excretion
- Degradation
A single unit membrane organelle is -
- Ribosomes
- Mitochondria
- Chloroplast
- Lysosomes
Three of the following statements regarding cell organelles are correct while one is wrong. Which one is wrong?
- Lysosomes are double membrane vesicles budded off form golgi apparatus and contain digestive enzymes.
- Endoplasmic reticulum consists of a network of membranous tubules and helps in transport, synthesis and secretion.
- Leucoplasts are bounded by two membranes lack pigment but contain their own DNA and protein synthesizing machinery
- Sphesrosomes are single membrane bound and are associated with synthesis and storage of lipids.
Vacuole in a plant cell
- Lacks membrane and contains air
- Lacks membrane and contains water and excretory substances
- Is membrane-bound and contains storage proteins and lipids
- Is membrane-bond and contains water and excretory
What does �lac� refer to in what we call be the lac operon?
- The number 1,00,000
- Lactose
- Lactase
- Lac insect
DNA fingerprinting refers to
- molecular analysis of profiles of DNA samples
- analysis of DNA samples using imprinting devices
- techniques used for molecular analysis of different specimens of DNA
- techniques used for identification of fingerprints of individuals
In negative operon
- co-repressor binds with repressor
- co-repressor does not bind with repressor
- co-repressor binds with inducer
- cAMP have negative effect on lac operon
Genes that are involved in turning on or off the transcription of a set of structural genes are called
- Operator genes
- Redundant genes
- Regulator genes
- Polymorphic genes
If the gene encoding the lac repressor is mutated so that it can no longer bind the operator, will transcription of that operon occur?
- Yes, but only when lactose is present
- No, because RNA polymerase can transcribe the genes
- Yes, because the operator will not be bound by repressor and RNA polymerase can transcribe the lac operon.
- No, because cAMP levels are low when the repressor is nonfunctional
Transcriptional regulation in prokaryotes can occur by
- a repressor binding an operator and preventing transcription
- an activator binding upstream from a promoter and positively affecting transcription
- different promoter sequences binding RNA polymerase more highly, resulting in more effective transcriptional ignition.
- All of the above
Post - transcriptional regulation includes
- binding of repressor on silencer regions
- transport of messenger RNA into the cytoplasm
- decreasing messenger RNA stability in the cytoplasm
- Both (b) and (c)
Which of the following is the first thing that happens when a signal molecule acts on a target cell?
- A transcription factor acts on the DNA
- The signal molecule binds to RNA
- A new protein is made in the target cell
- The signal molecule binds to a receptor.
A small segment of DNA contains the base sequences CGT. If an mRNA transcript is made that includes this DNA sequences, what will be the anticodon on the tRNA that will bind to corresponding mRNA codon for this DNA tripler?
- CGT
- GCA
- CGU
- GCT
A functional piece of mRNA has 66 codons. What is the maximum number of amino acids that could be present in the protein coded for by this mRNA?
- 22
- 64
- 65
- 66
A triplet base sequence in DNA reads ATT. What will be the corresponding mRNA anticodon, and amino acid called by this DNA?
- TAA; UTT; methionine
- TAA; AUU; no amino acid (= stop codon)
- UAA; AUU; no amino acid (= stop codon)
- CGG; GCC; alanine
The primary function of DNA polymerase is to
- add nucleotides to the growing daughter strand
- seal nicks along the sugar-phosphate backbone of the daughter strand
- unwind the parent DNA double helix
- prevent reassociation of the denatured present DNA strands.
The lagging daughter strand of DNA is synthesized in what appears to be the �wrong direction. This synthesis is accomplished by
- ligating (connecting) short Okazaki fragments that are synthesized in short in the �right� direction
- primase
- using multiple primers and DNA polymerase I
- Both (a) and (b)
RNA primers are necessary in DNA synthesis because
- DNA polymerase can only add to an existing strand of nucleotides
- DNA polymerase can only add to an existing DNA strand
- DNA primase is the first enzyme in the replication complex.
- All of the above
Compound tissue is defined as -
- Similar types of cells held together by connective tissue
- Different types of cells which are different in structure and function
- Different types of cells performing one function
- Similar cells at different regions performing many functions
Name the type of tissue that form gland
- Epithelial
- Muscular
- Squamous
- Cuboidal
Epithelial cells get nutrient material from -
- Neighbouring cells
- Blood vessels
- Lymph vessels
- Underlying
Which type of epithelial tissue is present in thyroid follicle?
- Squamous
- Cuboidal
- Transitional
- Columnar
Microvilli of epithelial cells -
- Increase surface area
- Protect the cells
- Engulf the foreign matter
- Give movements to the cells
Squamous epithelium is also called -
- Germinal epithelium
- Columnar epithelium
- Pavement epithelium
- Sensory epithelium
A connective tissue
- Has no matrix
- Covers the skin
- Has abundant matrix
- None of these
The intercellular substance found in connective tissue is
- Fatty in nature
- Muco-polysaccharide
- Mainly protein in nature
- All are correct
Tendons and ligaments belong to
- Muscular tissue
- Epithelial tissue
- Fibrous connective tissue
- Areolar connective tissue
Fibres present in connective tissue are -
- Reticular
- Elastic
- Collagen
- All of these
Which of the muscles are attached to bones?
- Smooth muscles
- Straited muscles
- Cardiac muscles
- All of these
Inter-calated discs are present in -
- Cardiac muscles
- Striped muscles
- Unstriated muscles
- Ligament
Which of the following ion is necessary for the contraction of a muscle and nerve impulse transmission?
- Na+
- K+
- Ca++ and Mg++ ions
- None of these
In the thin filament of skeletal muscle fibre, a small globular protein, that masks the active sites on the F-actin is
- G-actin
- Actin
- Tropomyosin
- Troponin
Which of the following possesses nodes of Ranvier?
- Medulllated nerve fibre
- Non-medullated nerve fibre
- Muscle fibre
- Medullated and non-meduallted nerve fibers