1. Which of the following is the primary basis for classifying
viruses?
A. Chemical composition
B. Host preference
C. Mode replication
D. Morphology
Ans: B. Host preference
- Classification of viruses is defined by host preference, viral
morphology, genome type auxiliary structures such as tails or envelopes. Viral
particles outside a host cell (so called virions) are inert entities with a
genome surrounded by a protective coat.
2. Which fungal groups does NOT reproduce sexually at all;
instead it has large distinctive asexual spores?
A. Ascomycetes
B. Basidiomycetes
C. Chytridiomycetes
D. Glomeromycetes
Ans: Glomeromyetes are an important group of fungi that live in
close symbiotic association with with
the roots of trees and plants. They reproduce asexually y producing
glomerospores and cannot survive without the presence of plant roots.
3. What is the basis of classifying cocci and bacilli
together in one group?
A. Cell Wall
B. Number of flagella
C. Nutrition
D. Shape
Ans: D. Shape
- In 1872, German biologist Ferdinand Julius Cohn classified
bacteria into four major types depending on their shapes (spherical, short
rods, threads and spiral). Cocci are types of bacteria are unicellular,
spherical or ellipitical shape. Bacilli are rod shaped or cyclindrical bacteria
which either remain singly or in pairs
4. Which of the following bacteria has no flagella?
A. Amphitrichous
B. Atrichous
C. Lophotrichous
D. Peritrichous
Ans: B. Atrichous
- Bacteria may be classified according to the presence and absence
of flagella. Bacteria without flagella are called atrichous. Monotrichous are
bacteria with flagellum attached to one and the bacteria cell. Lophotrichous
are bacteria with flagella attached to one end of the bacteria cell.
Amphitrichous are bacteria will bunch of flagella arising from both end of the
bacteria cell. Peritrichous are bacteria with flagella that are evenly
distributed surrounding the entire bacterial cell.
5. A bacterium retained the Gram stain when washed with absolute
alcohol and acetone. How will you classify the bacterium?
A. Gram positive
B. Gram negative
C. Miscellaneous staining
D. Not enough information given
Ans: A. Gram positive
- In 1884, Danish scientist Hans Christian Gram devised a method
to differentiate two types of bacteria based on the structural differential in
their cell wall. In his test, bacteria that retain the crystal violet dye do so
because of a thick layer of peptidoglycan and are called Gram-positive
bacteria. In contrast, Gram-negative bacteria do not retain the violet dye and
are colored red or pink. Chemically, Gram stain is a weak alkaline solution of
crystal solution of crystal violet. Compared with Gram-positive bacteria,
Gram-negative bacteria are more resistant against antibodies because of their
impenetrable cell wall
6. Which of the following disease is caused by virus?
A. Cholera
B. Rabies
C. Tetanus
D. Tubercolosis
Ans: B. Rabies
-Rabies infection is caused by the rabies virusis required is
spread through the saliva of infected animals. Infected animals can spread the
virus by biting another animal or a person. Tetanus, also called lockjaw is a serious
infection caused by Clostridium tetani ; this bacteria producers a toxin that
afftects the brain and nervous system. A bacterium called Mycobacterium
tuberculosis.
7. Which is the causative agent of mad cow disease
A. Bacterium
B. Prion
C. Virus
D. Worm
Ans: B. Prion
- Mad cow disease is an infectious disease caused by prions that
the brains of cattle. It is a fatal disease that slowly destroy the brains and
spinal cord (central nervous system) in cattle. The actual name of the disease
is bovine spongiform encephalopathy
(BSE) a name refers to the changes seen in brain tissue affected cows, Prions
are protein molecules that do not contain DNA or RNA and can cause disease in
animals.
8. Which prevent/s the stomach from being evaded by most
microbes?
A. Acids
B. Bile
C. Digestive enzymes
D. Peristalsis
Ans: A. Acids
- Parietal cells in the stomach secrete roughly two liters of acid a day in the form
of hydrochloric acid. In the stomach functions to kill bacteria. Gastric juice
consists of HCI and pepsin and can kill bacteria within 15 minutes when the pH
is less than 3.0.
9. Which is a sign of infection?
A. Cough
B. Fatigue
C. Nausea
D. Sore throat
Ans: A. Cough
- Most coughs are caused viral infectious. Although coughing can
be a sign of a serious illness more often, it will clear up on its will clear
up on its own without the need for medical attention.
10. Which bacteria multiply in the blood?
A. Fungemia
B. Protistemia
C. Speticemia
D. Viremia
Ans: C. Speticemia
- Septicemia is a serious bloodstream infection. It’s also known
as bacteremia or blood poisoning. Septicema occurs when a bacterial infection
occurs elsewhere in the body, such as in lungs or skin enter the blood stream
11. All are indirect transmission modes of disease spread EXCEPT
_____________ .
A. placental transfer
B. droplet in the air
C. eating contaminated food
D. bites from biological vectors
Ans: A. placental transfer
- Direct contact infections spread when disease-causing
microorganisms pas from the infected person to the healthy person via direct
physical contact with blood or body fluids VERTICAL TRANSMISSION happens when
micro organism pass from a mother to her unborn baby, through the placenta.
German measles and HIV can pass this way HORIZONTAL TRANSMISSION happens when
microorganism pass from one person to another by touching, kissing or sexual
intercourse. Indirect contact happens when microorganism are carried to a
person in some way , instead. Indirect contact happens when microorganism BORNE
TRANSMISSION involves an object carrying the disease-causing microorganism
VECTOR-BORNE TRASMISSION involves an animals such as an insect. For example malaria transmitted by
mosquitoes and plague by fleas.
12. Dinoflagellates are known for producing red tides. In what
way are they beneficial?
A. They kill off unnecessary fishes
B. They form limestone when they die
C. they glow to guide fishermen t night
D. They form zooxanthellae that provides coral reef with nutrients
Ans: D. They form zooxanthellae that provides coral reef with
nutrients
- zooxanthellae is a term
for any dinoflagellate that participates in symbiosis with sponges. Coral,
clams, Mollusk, flat worms jelly fish , etc. zooxanthellae are the symbiotic
algae that live within the hard or stony corals. The symbionic relation is
based on the corals inablilty to generate sufficient amounts of foods and the
algae’s ability for photosynthesis and converting chemical elements into
energy. The coral in return provides protection as wel as nutrient rich
environment for excellent algae growth.
13. Which of the following is/are an important conclusion/s in
Gregor Mendel’s experiments ?
I. An individual inherits one such units from each parent for each
trait
II. A trait may not show up in an individual but can still be
passed to the next generation.
III. The inheritance of each trait is determined by “units” of
“factors” that are passed on to go descendents unchanged.
A. I only
B. I and II only
C. II and III only
D. I, II and III
Ans: D. I, II and III
- All the three statements are major points of Gregor Mendel’s
expirements.
14. The gene for seed color in pea plants exist in two forms.
There is one form or allele for yellow seed color (Y) and another for green
seed colors (y). Which law describes this condition?
A. Law of Dominance
B. Law of Inheritance
C. Law of independent Assortment
D. Law of segregation
Ans: D. Law of segregation
- Law of Segregation(Mendel First law) states that during the
formation of reproductive cells (gametes) pairs of hereditary factors (genes)
for specific trait separate so that chance determines which factor for a
particular trait is inherited traits will
be dominant and the other recessive unless both factors are recessive.
All these three are parts of Mendel’s Laws of Inheritance.
15. Based on the findings on Mendel’s dihybrid cross experiments,
he was able to formulate the Law of Independent Assortment. Which of the
following BEST describes this law?
A. The biological selection of an allele for one trait has nothing to do with the
selection of an allele for any other
trait
B. During gamete formation. The alleles for each gene segregate
from each other so that each gamete carries only one for each gene.
C. Paternal and maternal chromosomes get separated in meiosis and
the alletes with the traits of a character are separated into two different
gametes
D. Some alleles are dominant while others are recessive; an
organism with atleast one dominant allele will display the effect of the
dominant allele
Ans: A. The biological selection of an allele for one trait has nothing to do with the selection
of an allele for any other trait
- In Mendel’s monohybrid crosses, an idealized 3:1 ratio between
dominant and recessive phenotypes resulted. In dihybrid crosses, however he
found at 9:3:3:1 ratios. This shows that each of the word alleles is inherited
independently from the other, with a 3:1 phenotypic ratio for each. Choices B
and pertain to the Law of segregation while Choice D refers to the Law of
Dominance.
16. What is the main function of chromosomes?
A. They house the DNA
B. They carry genetic information
C. They build the right protein for every cell
D. They caralyze the assembly of amino acids into protein chains
Ans: B. They carry genetic information
- Chromosomes are threadlike structure of nucleic acids and
protein found in the nucleus of most living cells, carrying genetic information
in the form of genes. Genes
17. What are the sex chromosomes of a male mammal?
A. XX
B. XY
C. YY
D. XYY
Ans: B. XY
- For mammals, the sex chromosomes carried by the sperm determines
the sex of the offspring. A male offspring is produce if an egg is fertilized
by a Y-bearing sperm, and a female offspring is produce if an egg is fertilized
by an X-bearing sperm. Male has XY chromosomes while XX chromosomes.
18. The dominance of an allele may imply that is dominant in the
population as a whole. Therefore, the most common allele is always dominant.
A. Absolutely true
B. Absolutely false
C. Not always
D. No enough information given
Ans: C. Not always
- The most common allele is not always dominant. In humans allele that causes a form of dwarfism known
as achondroplasia dominant but it very rare just like the dominant allele that
causes Hunting disease, progressive brain disorder.
19. When Mendel crossed a plant derived from a green seed with a
plant grow from a yellow seed the off spring could be all yellow, or they could
be a mix of green and yellow peas. What does this mean ?
A. The yellow seed trait is a recessive trait
B. The green seed trait is a dominant trait
C. Green seed color is dominant over yellow
D. Yellow seed color is dominant over green
Ans: D. Yellow seed color is dominant over green
- Since the offspring could be all yellow or a mix of green and yellow peas, the yellow
seed trait is said to be dominant over green. Although Mendel reffered to
traits as dominant or recessive. Modern biologist reserve these terms for
alleles. When two different alleles are present in an organism, the dominant
allele may ask the expression of the receive allele. The allele, however, is
still present.
20. To whom shall a color-blind man (cY) pass his defective
allele?
A. Sons
B. Daughters
C. Both sons and daughters
D. Grandsons and granddaughters
Ans: B. Daughters
- A color blind man (cY) will pass his defective allele only to
his daughters, because only his daughters because only his daughters inherit
his X chromosomes. Usually the daughters will have normal color vision because
they will also inherit a normal C allele from their mother who is very likely
homozygous normal (CC)
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