Biology Flashcards
In cats, black colour is caused by an X-linked allele at this locus cases orange colour. The heterozygote is tortoise-shell. What kinds of offspring would you expect from the cross of black female and orange male?
Tortoise Shell female; Black male
Which of the following show 9+0 arrangement of microtubular triplets?
Centrioles and basal bodies
Which of the following belongs to the tertiary hair?
-none of the answers is correct
The maximum volume of air that can be moved in and out during a single breath is called?
Vital capacity
Gene transcription takes place in?
Mitochondria and Nucleus
The outer to inner sequence of tissue layers in a post-gastrulation vertebrate embryo is?
Ectoderm -> mesoderm -> endoderm
Select the most correct statement?
The formation of a sperm is known as spermatogenesis
select the statement that best describes the DNA replication fork?
The leading strand can be synthesized in a continuos process from a singel RNA primer
select the statement that best describes the DNA replication fork?
The leading strand can be synthesized in a continuos process from a singel RNA primer
The leading and the lagging DNA strands differ in that?
the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is syntheszied in the opposite direction
Select the statement that most correctly describes function of hormones secreted by the pancreas?
glucose regulation
Select the statement that most correctly describes the nucleus of a eukaryotic cell?
Nucleoli are dense staining areas and one or more of them can be present
The process of capturing a substance or particle from the cell by engulfing it with the cell membrane is?
Endocytosis
The structure of the neuron that conducts impulses from the cell body is?
Axon
The site of ribosomal subunit assembly is?
Nucleolus
Mutations will typically ……. the genetic diversity in a population:
Increase
Select the statement that most correctly describes the differences between prokaryotic and eukaryotic cells?
Bacterial cells can exist as independent unicellular organisms or part of multicellular organisms
Select the statement that most correctly describes the genetic code:
There are 64 amino-acid coding codons
Where is the majority of water reabsorbed?
Proximale tubule of nephron
Select the statement that most correctly describes the process of mitosis?
Chromosomes are maximally condensed at the end of metaphase
A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane and mitochondria. It could be following cell?
a plant or an animal cell
Which of the following vitamins are recommended to be taken with fats?
Vitamin A and D
Select the statement that most correctly describes immunity?
All immune system responses are specific
Select the statement that most correctly describes cellular microfilaments?
Actin mediates fibroblast movement via rearrrangerment of its flagments
Picture showes chromosomes in eucaryotic cell. Recognise and name the phases of the cell cycle in the picture:
Anaphase
Select the statement that most correctly describes meiosis?
During the prophase I crossing over takes place
?????
Xrecesif
Select the most probable statement:
Conjugation is referred to as the bacterial equivalent of sexual process
Alternate forms and a gene having the same position a pair of chromosomes and affecting the same trait are called?
Alleles
Identical twins usually result from fertilisation of:
none of the answers is correct
An achondroplastic dwarf man with normal vision marries a colour-blind women of normal height. The mans father was 6 feet tall, and both womans parents were of average height. Achondroplastic dwarfism is autosomal dominant, blindness is X-linked recessive. What proportion of their male children would be colour-blind and normal height?
None of the answers is correct
Which of these associtations is mismatched?
-right ventrivle- pulmonary
-left ventricle -aorta
-inferior vena cava- right atrium
-Superior vena cava- right atrium
-all answers are correct
The thin filaments of a muscle fibre are made up of:
Actin
In which of the following would you usually find telomeres?
Human Chromsomes
All offspring of a white hen and a black rooster are gray. The simplest explanation of this pattern of inheritance is:
incomplete dominance
Which of the following organs and their main functions are correctly paired?
Liver: synthesis of insulin
Gallbladder: bile storage
The F1 offspring of Mendel`s classic pea cross always looked like one of the two parental varieties because:
one phenotype was completely dominant over another
Which of the following bones doesn`t take part on the formation of the orbit?
Ethmoid Bone
Which of the following is present in a prokaryotic cell?
ribosome
In sickle-cell disease, a single subsititution of an A by T on the B-globin gene causes the resultant protein to have altered properties, but to be of normal size. Select the term that most accurately describes this type of mutation?
Missense mutation
Diploid cell has 18 chromosomes. If a pair of homologous chromosomes fails to separate during anaphase of meioses II, what will be the chromosome number of the four resulting gametes?
10; 8; 9; 9
Which is the fundamental difference between prokaryotic and eukaryotic cell?
Presence of the nucleus enveloped by a membrane
Which of the following historical dates is correct?
The birth of the first cloned animal -Dolly the sheep- was published in 1997
The structure of deoxyribonucleic acid was discovered in 1953 by:
J.D Watson and F.Crick
The ability to reproduce themselves is a property that viruses share with living systems. Viruses can therefore replicate:
Only in a metabolically active cell
Which order of living systems by their level of organisation is correct?
Cell→organ→organism→community of organisms
Which of the following are classeified as non-cellular organisms?
Bacteriophages
Which of the following statements on HIV and its hosts is false?
HIV infects T-lymphocytes, i.e the cell relasting antibodies into blood plasma
Which of the following statements is false?
The closed blood circulation system was discovered by K. Landsteiner
The rate of simple diffusion across the plasma membrane depends on:
concentration gradient
DNA is present in?
Mitochondria
A differentiated cell of an organisms and the zygote this organism developed from are characterised by:
Identical Genomes
Which of the following mechanisms of neural exitation is true?
Changes in neuron plasma membrane permeability for Na+ and K+ ions
Which of the following is the regular component of a bacterial cell?
Cell Wall
Which is the correct order of cell cycle phases?
G1 –> S –> G2 –> M
Thickness of the plasma membrane is?
7,5nm
The flagellum of a eukaryotic cell is similar in ultrastructure to?
Cilium
Which of the following is not the product of transcription?
DNA
Which of the human body cells could be visible with the naked eye?
Mature oocyte
In which of the following cell structures does protein synthesis take place?
Mitochondria and cloroplasts
In which of the cell cycle phases does nuclear DNA replicate?
S
Which of the statements concerning viruses is true?
Viruses include only one kind of nucleic acid. either DNA or RNA
The primary structure of a protein molecule is determind by a sequence of:
Nucleotide triples in mRn
Wich of the following statements on the biosynthesis of nucleic acids and proteins is fals?
A sequence of amino acids in a polypeptide chain is termed a structural gene
Translation is a process by which genetic informasjon is translated from:
mRNA into proteins
dexyribonucleotides is complementary to T during DNA replication?
A
Both the alpha helix and the beta sheet are involved in the arrangement of:
Secondary tstructure of proteins
RNA synthesic takes place in:
Mitochondria and chloroplasts
Transcription is a process by which genetic information is transferred from:
DNA to mRNA
On transcription of an AAC triplet from DNA, which triplet is formed on a corresponding mRNA?
UUG
A bacteriophage is
Virus that lyses bacteria
A flagellum composed of microtubular bundles is responsible for locomotion of:
Sperm Cells
DNA polymerase is an enzyme that?
Functions in chloroplasts and mitochondria
When both male and female gonads are present in one and the same organism, we talk about?
Hermaphroditism
The ladder-like nervous system is found in?
Flatworms
Amnion is
Inner foetal membrane
Which of the following images is projected on the retina of a vertebrate eye?
Reverse, reduced
Transmission of a nerve impulse across a synapse is facilitated:
In a Chemical way using a mediator
Which of the following statements on fungi is not in agreement with the current knowledge?
Amitosis is the form of nuclear division typical of fungal cells
Antibiotics are the products of:
Bacteria and moulds
Which of the following diseases is transmitted by the tse-tse fly?
Sleeping sickness
In his experiments leading to the discovery of genetic laws, J.G. Mendel used the following organism:
Pisum sativum
Which of the following types of nucleic acids is a carrier of anticodon:
tRNA
Loss of one nucleotide in a DNA molecule has generally:
Greater effect Than nucleotide substitution
When crossing individuals with genotypes AaBb and AaBb, the ratio of phenotypes (A,B dominant alleles, a,b recessive alleles) will be as follows:
9:3:3:1
A chromosome of prokaryotic cells:
is made of one, usually circular double-stranded DNA molecule
Parthenogenesis
Is a form of sexuel reproduction in which females produce eggs that develop without fertilisation
Transduction is the process by which DNA is transferred from one bacterium to another by:
Phage
A phenotype is
-a set of all observable traits of cell or an organism resulting from an interaction of the environment and the genotype
The alleles of a givien gene differ from each other in that:
-each carries a different mutation of a given gene
Homologous chromosomes:
Pair during meiosis
An allele is:
A alternative form of a Gene found at the same lotus on homologous chromosomes
One of Mendel`s key discoveries was that:
-organisms had two hereditary factors for all traits
Which of the following is true?
The recessive allele is expressed only when the dominant allele is missing
Which of the following is true?
Chromosome banding is a procedure for identification of structural abnormalities in chromosomes
Chromosomes line up in the center of the cell during:
Metaphase
In the complete dominance of A over a, the heterozygote Aa has a phenotype
Identical with AA
The number of diffferent phenotypes in F2 generation of dihybrids with complete dominance (AaBb x AaBb) is:
4
Gene mutations is:
Can be a results of a change in the nucleotide Number of a gene
relationship between A and B alleles for the ABO blood group is:
Codominance
Which blood types can be found in the children whose both parents have O blood groups?
O
A genotype is
The set of all genet of the organism
Which of the following statements concering the genetic code is false?
Genetic code includs 20 codons to specify 20 amino acids found in proteins
Plasmids are
Carries of a part genetic informtion in bacteria
The karyotype in Down syndrome is characterised by the presence of an extra copy of genetic material on the:
Chromosomes 21
Genetic transformation is:
Alteration og genetic information of a cell following incorporation of foreign DNA
Crossing-over is:
-Exchange of genetic material between homologous chromosomes
The part of the human digestive system engaged in food digestion and absorption of nutrients is:
Small intestine
Human saliva contains enzymes that digest:
Starch
what is the role for red blood cells?
Oxygen transfer
In the human heart, semilunar valves are found between:
The ventricles and the major arteries
Insulin is a hormone that:
facilitates glucose metabolism in cells
The nerve centre controlling many autonomous functions is located to:
Hypothalamus
The human eye can perceive light waves in the range of:
400 –> 750nm
The full prenatal development in humans lasts for?
270 days
The human thorax has
12 pairs of ribs
Which of the following responds to a change in body position?
Mechanoreseptors
The cancer disease of white blood cells is called?
Leukemia
One mm3 of human blood contains
5.10(6) erythrocytes
Insulin is produced in the pancreas in response to
an increase in the glucose plasma level
Cell-mediated immunity is provided by
T - lymphocytes
The human spinal column consists of the following vertebrae:
7 cervical 12 thoracic 5 lumbar 5 sacral and coccyx
Which of the following statements is false?
The human skeleton is made up of more than 300 bones of all shapes and sizes
Human being can perceive sound at frequencies?
Between 16 and 20 000 Hz
The principle of blood clotting in vertebrates is based on:
conversion of soluble fibrinogen into insoluble fibrin
Platelets are:
cytoplasmic fragments of large bone marrow cells
What blood volume the heart of a human adult at rest can pump into the pulmonary circulation in one minute?
5L
direct source of energy for muscle contraction comes from:
Glucose
the most important immediate source of energy for humans includes:
Sugars
Amylase is the enzyme that digests:
Starch
Bile is produced in:
Liver
The oldest paleontological evidence suggesting the existence of living cells is found in sediments:
3.7 billion years old
Homo sapiens neanderthalensis lived:
200.000 –> 30.000 years ago
The human species continues to exist owing to:
Reproduction of individuals
Darwin postulated that major factor influencing evolution:
Is natural selection
The first eukaryotic cells appeared about 1.5 billion years ago. This conclusion was drawn from:
-Age of the sediments in which the fossil remains of algal cells were detected by microscopy
Darwin`s theory of Evolution is concerned primarily with:
Origin of species
Australopithecus africanus is thought to have been a direct ancestor of modern humans. Which of the following facts concerning Australopithecus is not in agreement with paleontollogical evidence?
He used of Stone tools
Ecological niche of a species:
Is a space which the species occupies in its ecosystem
All organisms living together in area constitute
Biocenose
Plants utilise for photosynthesis:
Visible light
Which of the following gases is responsible for the greenhouse effect?
CO2
Which of the following statements concerning the lymph fluid is false?
Lymph fluid is produced in lymph nodes
