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The flow of genetic info., png-clipart-dna-nucleotide-rna-nucleic-acid…
The flow of genetic info.
The cell
The nucleus
Chromosomes
Genes
Alleles
Variations of the genes
A length of DNA that codes for a protein
They determine all things about an individual and they are inherited from the parents.
Each species has its own number and variety of genes
This is what makes their body chemistry, their appearance and their behaviour different form those of other organisms.
Humans have
46 chromosomes
inside each of their cells, all with many genes of them.
Every cell in one's body has an exact copy of all of one's genes. So, one's genes makes one unique.
Haploid
nucleus is a nucleus with a single set of unpaired chromosomes.
Diploid
nucleus is a nucleus containing two sets of chromosomes
Homologous chromosomes
are the two chromosomes of a pair.
4 more items...
The only cells that have half of the chromosomes are the gametes, which would be the sperm and the egg. Together they form the zygote, which has 46 chromosomes.
Inheritance
: the transmission of genetic information from generation to generation
Gametes have half to preserve the number of chromosomes of the species
A thread like structure of DNA, carrying genetic information in the form of genes
Each one contains one very long molecule of DNA, which carries a code that instructs the cell about which types of proteins it should make.
Cell division in eukaryotic cells
Mitosis
Nuclear division giving rise to genetically identical cells
It takes place when an organism is growing or repairing a damaged part of it body
It also takes place in asexual reproduction
Before mitosis, the chromosomes in the parent cell are copied and each copy remains attached to the original one, so each chromosome is made up of two identical threads joined together.
The two threads are chromatids, and the point where they are held together is called centromere
Two new cells are formed, each with one copy of each of the chromosomes. As the new cells grow, they make new copies of each chromosome, ready to divide again.
The chromatids separate to replicate the cell having the same number of chromosomes
Meiosis
Nuclear division giving rise to cells that are genetically different
Reduction division in which the chromosome number is halved from diploid to haploid, resulting in genetically different cells
It occurs in the ovaries and testes
Meiosis produces
genetic variation
as its result are cells genetically different from the parent cell.
For variation in the population for evolution
Natural selection
Gametes with
half the number of chromosomes
and each of them is different
To preserve the umber of chromosomes of the species
Meiosis 1
The pair of homologous chromosomes separate having the same number of chromatids
If one pair of homologous chromosome does not separate
Non disjunction
Gametes with abnormal number of chromosomes obtained
Abnormal karyotype
One extra chromosome
1 more item...
Monosony
It increases the chances the age of the mother
Step by step
Homologous chromosomes pair together. Crossing over takes place.
Homologous chromosomes separate. One from each pair goes into each daughter cell.
Meiosis 2
The sister chromatids separate in the chromosomes. One chromatid of each kind goes into each daughter cell.
DNA
It determines all living organisms genetic features
It forms the genetic code
99% of the DNA is the same in every humans
It is made of nucleotides, which are the building blocks
DNA is a nucleic acid, as well as RNA
Each nucleotide is made up of 3 parts
A five carbon sugar/ a pentose sugar
A phosphate group
A nitrogenous base
Four types
A, adenine
T, thyme
C, cytosine
G, guanine
They are joined by hydrogen bonds
A and T are complementary
C and G are complementary
Its structure is a double helix made up of two strands
The other bonding is between sugar and phosphate
Differences with RNA
DNA
Double stranded
Sugar: deoxyribose
G, C, A, T
RNA
Single stranded
Sugar: ribose
G, C, A, U
Uracil
Both made of nucleotides
