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BIOLOGY > Final Test > Flashcards

Final Test Flashcards

1
Q

What is a gene?

A

Basic unit of hereditary

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2
Q

What is a chromosome?

A

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

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3
Q

What is a locus?

A

A specific region or spot on a chromosome where a gene is found

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4
Q

What is an allele?

A

One or two on more forms of a given gene

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5
Q

What is a dominant allele?

A

Relationship between to alleles in which one allele masks the effect of the other (recessive) allele

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6
Q

What is a recessive allele?

A

Allele expressed only in the homozygous state - bb- when in the heterozygous state- Bb - it is masked by the dominant allele

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7
Q

What is homozygous?

A

Both alleles being the same at one locus =BB or bb

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8
Q

What is heterozygous?

A

2 different alleles at one locus = Bb

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9
Q

What is a genotype?

A

Genetic makeup of an organism

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10
Q

What is a phenotype?

A

The observable makeup of an organism

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11
Q

What is the use of test crosses?

A

To find out he genotype of an unknown that shows a dominant phenotype you cross it with a homozygous recessive and this will tell you if the unknown is heterozygous or homozygous dominant

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12
Q

How is the punnett square used?

A

Used to determine all the possible combinations of offsprings from two parents

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13
Q

What is the law of independent assortment?

A

The Principle of Independent Assortment describes how different genes independently separate from one another when reproductive cells develop.

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14
Q

What is the law of segregation?

A

Each individual carries a pair of factors (2 alleles) for each trait that segregate during the formation of gametes.

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15
Q

What is codominance?

A

Full expression of both alleles

AB blood group

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16
Q

What is incomplete dominance?

A

When the phenotype of the heterozygote is intermediate between the 2 parental extremes

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17
Q

What is polygenic inheritance?

A

Polygenic inheritance concerns a pattern of inheritance in which the interactions of two or more functionally similar genes determine phenotype.
these are examples of traits that exhibit polygenic inheritance; they are governed not by interactions among two or more genes

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18
Q

What is sex linked inheritance?

A

If a gene is present on one sex chromosome but not on the other, its pattern of inheritance is sex linked.

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19
Q

How do mutations affect human diseases?

A

Cause genetic disorders

Cancer

Prevent proteins from works properly

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20
Q

What is the relationship between human disease and recessive alleles?

A

Recessive inheritance means both genes in a pair must be abnormal to cause disease.

Example: Diseases like sickle cell anemia come from homozygous recessive alleles ss

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21
Q

What is hemophilia? How is it caused?

A

If a gene is present on one sex chromosome but not on the other, its pattern of inheritance is sex linked.
 Hemophilia

a medical condition in which the ability of the blood to clot is severely reduced, causing the sufferer to bleed severely from even a slight injury

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22
Q

What is sickle cell anemia ? How is it caused?

A

These cell have a change in r- group this produces hemoglobin that stick together and form fibers which then get stuck in capillaries (small blood cells)

Sickle cell disease is caused by a mutation of a single nucleotide located within a restriction sequence in the human Beta globin gene .

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23
Q

What is a chromatin?

A

A mixture of DNA and protest that form the chromosomes found in cells

24
Q

What is the relationship of chromosomes, genes and DNA

A

A chromosome is made up of DNA molecules and each chromosome contains multiple genes

25
Q

What is a nucleic acid?

A

a complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain.

26
Q

What is the structure of a nucleotide?

A

A nucleotide consists of a phosphate, a sugar, and a nitrogenous base.

27
Q

What are purines?

A

The purines are adenine and guanine.

28
Q

What are pyrimidines?

A

The pyrimidines are cytosine and thymine and uracil

29
Q

What are the rules for base pairing?

A

A with T: the purine adenine (A) always pairs with the pyrimidine thymine (T)
C with G: the pyrimidine cytosine (C) always pairs with the purine guanine (G)

30
Q

What an the rules for mRNA base pairings?

A

Instead of a to t it is a to u

31
Q

What are the “proof reading” enzymes of DNA replication process?

A

The DNA polymerase I and polymerase III act as proof readers of the newly formed DNA.

32
Q

How is DNA replicated?

A

How is DNA replicated? Replication occurs in three major steps: the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment.

33
Q

What is semiconservative replication?

A

after one round of replication, every new DNA double helix consisted of one strand of old DNA bound to one strand of newly synthesized DNA.

34
Q

What is the leading and lagging strands of DNA?

A

The leading DNA strand is synthesized continuously.

The lagging DNA strand is synthesized discontinuously in segments of nucleotides called Okazaki fragments,

35
Q

Which enzymes are used for both the leading and the lagging strand?

A

Helicase, primase, and two molecules of DNA polymerase III

36
Q

What is the process of transcription?

A

Transcription cannot begin until gene activating chemicals stimulate histone proteins

The transcription factors bind to the promotor, a special DNA sequence that contains the start point of the gene.

pre Messenger RNA (mRNA) “forms” upon on half of this DNA strand. (RNA has the complementary codons of the other DNA strand).

Summary-Transcription happens when RNA is copied from DNA. And occurs in the NUCLEUS

37
Q

What is the process of translation?

A

mRNA attaches to a RIBOSOME (workbench)

Transfer RNA (tRNA) attaches to a free amino acid in the CYTOPLASM on one end.

On the other end, tRNA has an anticodon which consists of 3 nucleotide bases (triplet).

The anticodon is attracted to the codon on mRNA and attaches in an assembly line manner.

The union of mRNA codons to tRNA anticodons links a chain of amino acids to make a protein

The anticodon is attracted to the codon on mRNA and attaches in an assembly line manner.

The union of mRNA codons to tRNA anticodons links a chain of amino acids to make a polypeptide

38
Q

How is RNA polymerase used and why is it important In the expression of a gene?

A

RNA polymerase (RNAP) is the central enzyme of gene expression, which transcribes DNA to RNA

39
Q

What is the difference between DNA and RNA ?

A

DNA
replicates and stores genetic information.
It is a blueprint for all genetic information contained within an organism.
DNA is a much longer polymer than RNA.
in DNA is deoxyribose, which contains one less hydroxyl group than RNA’s ribose.
The bases in DNA are Adenine (‘A’), Thymine (‘T’), Guanine (‘G’) and Cytosine (‘C’).
Adenine and Thymine pair (A-T)
Cytosine and Guanine pair (C-G)
DNA is found in the nucleus
more stable molecule than RNA,

RNA
RNA converts the genetic information contained within DNA to a format used to build proteins, and then moves it to ribosomal protein factories.
RNA contains ribose sugar molecules,
RNA only has one strand, but like DNA, is made up of nucleotides.
RNA strands are shorter than DNA strands
Adenine and Uracil pair (A-U)
Cytosine and Guanine pair (C-G)
RNA, containing a ribose sugar, is more reactive than DNA

40
Q

What are the types of RNA and how do they function in protein synthesis?

A

mRNA (messenger RNA): it provides the template for protein synthesis during translation

tRNA (transfer RNA): it brings amino acids and reads the genetic code during translation

rRNA (ribosomal RNA): it plays a structural and catalytic role during translation

41
Q

How does tRNA bind to an amino acid?

A

There are enzymes involved, aminoacyl tRNA synthetases. These enzymes are able to recognize a specific tRNA and a specific amino acid and catalyze their binding.

42
Q

What is the use of aminoacyl-tRNA synthase?

A

The aminoacyl-tRNA are enzymes that play a role in protein synthesis, pairing tRNAs with amino acids for decoding mRNAs according to the genetic code.

43
Q

How is mRNA made?

A

mRNA is created during transcription. During the transcription process, a single strand of DNA is decoded by RNA polymerase, and mRNA is synthesized.

44
Q

What are introns?

A

a segment of a DNA or RNA molecule which does not code for proteins and interrupts the sequence of genes.

The pre-mRNA is spliced to remove introns (noncoding sequences).

The code for proteins is interrupted by sequences called introns.

The exons are found between the introns.

45
Q

What are exons?

A

The sections of the pre-mRNA that wind up getting translated

An exon is a region of the genome that ends up within an mRNA molecule. Some exons are coding, in that they contain information for making a protein

46
Q

What is added to the beginning and end of a spliced mRNA transcript?

A

Description of mRNA Splicing

Transcription and processing (which includes splicing) of the newly made mRNA occurs in the nucleus of the cell.

Once a mature mRNA transcript is made it is transported to the cytoplasm for translation into protein.

47
Q

How are the amino acids assembled at the ribosome?

A

The mRNA is then pulled through the ribosome; as its codons encounter the ribosome’s active site, the mRNA nucleotide sequence is translated into an amino acid sequence using the tRNAs as adaptors to add each amino acid in the correct sequence to the end of the growing polypeptide chain.

48
Q

Discuss the relationship between codons of mRNA and anticodons of tRNA?

A

In translation: the anticodon is attracted to the codon of mRNAthat attaches to the assembly line, this union on mRNA codons to tRNA anticodons links a chain of amino acids to make polypeptide

3 nitrogen base pairs are called a codon.

A codon is a nucleotide triplet which codes for a protein product that has a specific role or function

49
Q

Discuss the equation of DNA transcription to mRNA translation

A
50
Q

What is a mutation?

A

A mutation is a change in the DNA sequence of an organism.

51
Q

How does mutation affect the order of amino acids in a protein and the shape of a protein?

A

The specific shape and stability of a protein’s structure depend on networks of interactions between its amino acids. These networks can be altered by various mutations (amino acid changes), which can cause protein misfolding or destabilization.

52
Q

Does the mutation affect the specific function of a protein?how?

A

Sometimes, gene variants (also known as mutations) prevent one or more proteins from working properly. By changing a gene’s instructions for making a protein, a variant can cause a protein to malfunction or to not be produced at all.

53
Q

What is evolution and how is it affected by mutations?

A

Change in DNA proves evolution that genes change through generations

54
Q

What is nonsense mutations?

A

A nonsense mutation, or its synonym, a stop mutation, is a change in DNA that causes a protein to terminate or end its translation early

55
Q

what is a missense mutation?

A

A missense mutation is an alteration in the DNA that results in a different amino acid being incorporated into the structure of a protein.

56
Q

What is frameshift mutations?

A

An insertion or deletion involving a number of base pairs that is not a multiple of three, which consequently disrupts the triplet reading frame of a DNA sequence.

57
Q

What is DNA’s makeup? (Include a description of the sides and rings of the DNA ladder)

A

Two nitrogenous bases form the “rungs” of the ladder. On the outside there the phosphate group.

A rung consists of a pyrimidine base attached to a purine base which connect both strands of DNA to form a ladder.

This ladder is twisted in form.

BIOLOGY (8 decks)

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