C4: Cell and mole bio

self-made reviewer directly from the powerpoint

DNA is located in

chromosomes

What is a genome?

collective genetic information of an organism

What nature of the gene was discovered in 1865?

discrete units of inheritance by Gregor Mendel

What nature of the gene was discovered in the 1880s?

chromosomes

what nature if the gene was discovered in 1903

homologous chromosomes

what nature of the genes was discovered from 1909 to 1911?

Crossing over during Meiosis

what nature of the gene was discovered from 1911 to 1913?

Genes are mapped in order along the length of chromosomes

what nature of the gene was doscovered mfrom 1944 to 1952?

DNA as genetic material

what nature of the gene was discovered during 1953?

DNA structure

Mendel's work on garden peas became the foundation for:

genetics

Why did mendel chose garden peas in his work?

they have clearly definable 2 alternative traits

Mendel's experiment on his pea plants gave rise to:

Laws of Inheritance

Characteristics of organisms are governed by units of inheritance called

genes

What is an allele

2 forms of a gene that controls each trait

what is a gamete?

reproductive cell containing one gne for each trait

how many alleles are inherited?

2; 1 from each parent

what are the 4 concepts of geen as a unit of inheritance?

1. Characteristics of oraganisms are governed by units of inheritance 2. A reproductive cel called gametre contains one gene for each trait 3. 2 pairs of genes are segregated during gamete formation 4. Genes controlling different traits segregate independently of each other.

How was chromosomes first discovered?

in dividing cells under the light microscope

What happens to chromosomes during cell division?

they divide equally into two daughter cells

Before cell divion, chromosomeese are

already doubled

What is a homologous chromosomes?

one of the two pairs of chromatids that forms chromosomes

what happens to the homologous chromosomes during meiosis?

they associate to form a BIVALENT; then separate into different cells

to what concept in genes is the chromosmal behavior be correlated wityh

Mendelian Laws of Inheritance

genes on the same chromosome do not:

assort independently

the genes on the same chromosome are part of the same:

linkage group

the locations of the traits Mendel observed are

part of the same linkage group

Why is drosophilia used as a genetic tool?

they have 4 pairs of homologous chromosomes, they can mutate (from red eyes to white), easier to access and lays egg quickly, have shortwer life span

Linkage between alleles on the same chromosme is

incomplete

when can maternal and patrnal chromosomese can exchange pieces?

during crossing over or geentic recombination

what is a homolog/ homologue?

gene inherited in two species from a common ancestor

what is a chiasmata?

points where homologues are crossed

percentage of recombination between a pair of genes is:

constant

percentage of recombination between diffferent pair of genes can be

different

Positions of genes along a chromosome can be

mapped

what happens to the frequency of recombination when the distance increases?

frequency of recombination increases also

what are polytene chromosomes?

these are single chromosome found in cells that can undergo in consecutive genome replicatipon without breaking the nuclear envelope

how are polytene chromosomes formed?

when chromatids of diploid nuclei chromosomes duplicate successively during S-PHASE without segregation, the cable-like structure products are compacted to form one giant chromosome

function of puffs in polytene chromosome

visualization of gene expresion

siginifaincance of polytene chromosomes

observing specific band related to individual genes

building block of DNA

nucleotide

parts of a nuclotide

phosphate group, deoxyribose sugar, nitrogenous base

two types of nitrogenous bases?

purine, pyrimindine

Purine

Adenine Guanine

Pyrimidine

Cytosine Thymine

polarized structures of nucleotides have ends called

5' and 3'

what links the sugar and phosphates in the DNA

3' , 5'- phosphodiester bonds

Chargaff rules were established after

base composition analysis A\=T and C\=G

What is the structure of DNA based on the Watson-Crick proposal

double helix

DNA has \___ chains of nucleotides

two

The two chains of DNA are

antiparallel

what is the meaning of antiparallel?

run I opposite directions

the sugar-phosphate background in DNA is located at the \___, while the bases are \_____

outside of the molecule; inside the helix

what holds the DNA chain at their bases?

hydrogen bonds

the DNA molecular has \__ and \__ grooves

major and minor

what is the major groove?

the oxygen molecule in the deoxyribose ring is always pointed up in the correct orientation 5' to 3'

what is the minor groove?

the oxygen molecule in the deoxyribose ring is always pointed down in the correct orientation 5' to 3'

the two chains in DNA are \___ to each other

complementary

The 3 importance of the Watson-Crick proposal?

1. storage of genetic information 2. reolication of inheritance 3. expresion of the genetic message

what is supercoiling?

it is the coiling of the DNA in favor of many complex cell processes to take plaxce

when the DNA is more compact than its relaxed counterpart, it is then considered to be

supercoiled

an underwound DNA is \____ supercoiled while an overwound DNA is \___ supercoiled

negatively; positively

an underwould molecule assumes a \_____

negatively supercoiled conformation

what does negative supercoiling does to the DNA in cell nucleus?

it makes the DNA fit

what enxyme changes the DNA supercoiling?

topoisomerase

function of type II topoisomerase?

change supercoiled state by CREATING A TRANSIENT BREAK IN ONE STRAND OF THE DUPLEX

function of type I topoisomerase?

make atransient break in both ends of the DNA duplex

what is denaturation in DNA

its ability to separate into two strands

what is renaturation or reanneling?

it happens when a single-stranded DNA molecules reassocites

some of the products of the discovery of renaturation?

development of nucleic acid hybridization

what is nucleic acid hybridization?

complementary strands of nuclic acids from different sources can form hybrid molecules

Three classes of DNA reannealing and their sequence in increasing Cot

Highly repeated, moderately repeated, Nonrepeated

How many percent does highly repeated DNA sequences can represent the total DNA

1 to 10 %

what is a satellite DNA

short sequences; tend to evolve rapidly

what is a minisatellite DNA and its function

unstable; variable in population; basis of DNA fingerprinting

process of DNA fingerprinting

Restriction endonucleases digest the DNA and DNA fragments are separated via gel electrophoresis

what is microsatellite DNA and its functiom

shortest sequences in small clusters; detect genetic disorder

what happenes during Fluorescent in situ hybridization

DNA probe that is hybridized into chromosomes are used to determine position of satellite sequences

the process of Fluorescent in situ hybridization

1. fluorescent probes are generated towards a specific DNA sequence 2. Probed hybridize with DNA 3. Fluorescent spots determines gene/DNA location

what are the 2 types of moderately repeated DNA sequences

1. repeated DNA sequences with coding functions 2. repeated DNA sequences without coding fucntions

examples of repeated DNA sequence woth coding functions

genes for RIBSOSOMAL RNA and HISTONES

what products does repeated dna sequence without coding functions have

none. They do not have any gene product

repeated dna sequence without coding functions have 2 classes:

SINEs or LINEs

what are trinucleotide repeats

they causes mutations in repeating unit of 3 nucleotides

when trinucleotide repeats occur the mutant alleles are

highly unstable

when trinucleotide repeats occur what happens to the number of repeating units

increase when the gene is passed from parent to offspring

Type I diseases in expanision of trinucleotide repeats, which are all nuerodegeneratic disorders result from

expansion of CAG trinucleotides

huntington's disease is caused by \__ and from what gene

36 glutamine repeats in the huntingtin gene

the expanded glutamine repeats in huntington's disease are toxic to

brain cell

the type II diseases classified under the expansio of triucleotide sequence are present in

gene parts that do not code for an amino acid

what is polyploidization

whole genome replication; occurs when offspring receive more than 2 pairs of chromosomes

what is the function of the unequal crossing over of duplicated genes

generate changes in gene number

gne duplication happens within?

a portion of a single chromosome

how does gene duplication occur

unequal crossing over between misalogned homologous chromosomes

gene duplication played a major role in

evolution of multigene families

what genes are part of the globin genes?

myoglobin, hemoglobin, leghemoglobin

how was globin genes derived

duplication, gene fusion, divergence

what are pseudogenes

nonfunctional sequences that resembles globin genes

what is transposition

genetic elements moves within a chromosome

what are transposable elements

mobile elements that can move in the chromosome

funciton of the enzyme tranposase

facilitate insertion of transposons to the target site