Sttrcuture And Function Id Dna

Question 1

Genetics

Answer 1

science about heredity and variations of living organisms.

Question 2

variation

Answer 2

Variation is divergence of species in their biological properties.

Question 3

Heredity(inheritance)

Answer 3

The ability of organisms to transit their biological traits to their progenies

Question 4

Who did genetics originate from

Answer 4

Gregor Mendel

Question 5

Griffiths experiment

Answer 5

-Mice got injected with live smooth cells of pneumococcus and did
-Mice got injected with heat killed smooth cells and mice survived

-mice got injected with live rough cells of pneumococcus and survived
-mice got injected with mixed heat killed smooth cells and live rough cells and mice died.Live cells could be isolated from the dead mouse

Conclusion:transformation of rough cells into smooth cells killed mice

Question 6

What is the transforming principle

Answer 6

In 1943, O. Avery with colleagues showed that some morphological and pathogenic properties could be transferred from smooth pneumococcal strain to the rough by DNA extracted from the virulent smooth strain.

Question 7

Chargaff’s rules

Answer 7

Chargaff’s rules (1950):

1. Amount of purine is equal to the amount of pyramiding in dna

A% = T%
2.proportion of AT bases could be different from GC bases(variation is species dependant)

Question 8

DNA components

Answer 8

Each nucleotide includes at c carbon,phosphate and a nitrogenous base

Question 9

Complementary base pairing

Answer 9

-pyrimidien base=cytosine ans thymine
-purine =adenine and guanine

Question 10

Replication of dna

Answer 10

-Semi conservative replication
-every dna strand serves as a template for the synthesis of the complementary strand

Question 11

How are protein made from dna

Answer 11

DNA
Replication
Transcription
Translation
Protein

Question 12

Types of rna involved in protein synthesis

Answer 12

Messenger
Transfer
Ribosomal

Question 13

Genetic processes that contribute to variation

Answer 13

Mutations
Recombination
Transpositions

Question 14

Location of dna in the cell

Answer 14

In cytoplasm of prokaryotes
In nucleus, mitochondria and plastids of eukaryotes

Question 15

DNA coiling in the chromosome

Answer 15

-DNA surrounds histones (proteins) and forms nucleosomes.

-They are arranged into solenoids.

-Solenoids make chromatin loops (units of chromatin in the chromatids of chromosome).

A chromatid is one of two copies of a replicated chromosome.
During cell division, the copies are joined (and later segregated into daughter cells) at the region called the centromere

Question 16

Satellite dna

Answer 16

is highly repetitive DNA that is different in base composition from the majority of DNA in eukaryotic species. The majority of satellite sequences have increased AT content (65–80%)*. This difference allows to separate satellite DNA as one or more distinct bands during centrifugation with cesium chloride.
Some proportion of satellite DNA is a part of centromere structures (responsible for separation of chromosomes to daughter cells during cell division)

Question 17

How was satellite dna discovered

Answer 17

-genomic dna is fragmented and centrifuged
-when reaching equilibrium dna bands settle based on density

Question 18

Details of gene structure

Answer 18

Enhancer is bound by activator proteins (transcription factors) to start transcription.

The TATA box is a non-coding DNA sequence (known as a cis-regulatory element). It indicates a start of reading and decoding of a genetic sequence. Transcription factors bind TATA box and recruit RNA polymerase, which synthesizes RNA from DNA.
Details of gene structure

AATAAA is a conserved sequence of polyadenylation signal site

Question 19

Uni-parental inheritance:

Answer 19

Inheritance of traits from only one parent

Question 20

Bi parental inheritance

Answer 20

Inheritance of traits from both parents

Question 21

From organelle is variation controlled by

Answer 21

Variegation Trait is controlled by genes in cytoplasm

Question 22

Telomeres

Answer 22

=chromosomal ends(dna+ proteins)
-specialised DNA-protein complexes at the ends of chromosomes.
Telomeres are needed for protecting integrity of chromosomes and, therefore, for genome integrity

Question 23

Genome

Answer 23

Complete set of genetic in formation of an organism

Question 24

Plastome

Answer 24

Genome of plastids

Question 25

Mitopchondriome

Answer 25

Genome of mitochondria

Question 26

Epigenome

Answer 26

Description of all chemical modifications of dna ans histone proteins that regulate gene expression within the genome

Question 27

Genotype

Answer 27

Combination of alleles for a particular gene or locus

Question 28

Types of alterations to genetic material

Answer 28

-small changes in dna sequence
-rearrangemnts of genes and chromosomes
-deletions and insertions of dna sequences
-increasing or decreasing Chromosomal sets

Question 29

Types of impact of gene alteration

Answer 29

Neutral
Beneficial
Harmful

Question 30

Mutations

Answer 30

are random, inheritable (usually small) alterations in the sequences of a genome. Mutations can change the phenotype. Some of them (which are neutral) do not change the phenotype

Question 31

Mutagens

Answer 31

are physical or chemical factors that increase the rate of mutations (in this case they are called induced mutations).
Mutagens can modify DNA in different ways, but those changes are considered as mutations when they are inherited.

Question 32

Type of point mutations

Answer 32

Point mutations could be of two general categories:
- base–pair substitutions (one nucleotide is substituted with another);
- base–pair insertions or deletions (the nucleotides are inserted [added] or deleted

Effect :

Base–pair substitutions may lead to silent, missense, or nonsense mutations.
Insertions and deletions are mutations that have much more dramatic, disastrous effects on resulted proteins than substitutions do.
This is because mRNA is read as triplets of nucleotides (one triplet for one amino acid) during translation (protein synthesis); and the insertion or deletion of nucleotides alter the reading frame of grouped triplets, leading to a shift in genetic message (a frameshift mutation).

Question 33

Types of base pair substitition

Answer 33

ubstitution is called a silent mutation if it has no effect on the encoded protein (because of the redundancy of the genetic code: a few different triplets could encode the same amino acid).
A substitution is a missense mutation if the altered codon causes encoding for a different amino acid (makes not right sense).
A substitution is a nonsense mutation if a codon for an amino acid is converted into a stop codon (it terminates translation, and a protein could be truncated

Question 34

What type of mutation is sickle cell disease

Answer 34

a point missense mutation.
The allele causing sickle–cell disease differs from the wild–type (normal) allele by a single DNA base pair (A instead T leads to the synthesis of the aminoacid valine instead glutamine in the molecule of haemoglobin)

Question 35

Achondroplasia

Answer 35

Mutation which causes abnormality in cartilage formation that delays bone growth,active mutant receptor leads to shortened bones
50% chance of passing the gene to children

Answer 36

Hutchinson-Gilford progeria syndrome:
autosomal dominant syndrome

GGC mutates to GGT

Question 37

Translocation associated with chronic myelogenous leukemia (CML)

Answer 37

CML patients possess an abnormally short chromosome 22 (called Philadelphia chromosome), and an abnormally long chromosome 9 that are resulted from the reciprocal translocation. They have leukaemia, due to unregulated growth of predominantly leukocytes in the bone marrow (disorder of stem cell differentiation).

Question 38

Down syndrome

Answer 38

most common type of viable human aneuploid
Characteristic facial features for a child with Down syndrome.
The other signs are short stature, heart defects, susceptibility to respiratory infection, and mental retardation. The patients are prone to leukemia and Alzheimer′s disease.
.
They have a shorter life span (some live to middle age). Most are sterile and sexually underdeveloped.

Question 39

Basic biological functions of dna

Answer 39

In general:
Functions in heredity (based on exact copying of DNA during replication).
Functions in variations (based on recombination of DNA and different types of genome alterations – mainly as errors in replication of DNA and segregation of chromosomes). DNA variations are implicated in evolution of species. In many cases, however, they lead to serious diseases

Coding functions

Non coding functions