DNA genes and chromosomes Flashcards
Define DNA
A DNA (deoxyribonucleic acid) double helix is the fundamental unit of our genetic material. One
molecule of DNA is made up of a sugar group (deoxyribose), a phosphate group and a base. There
are four bases: Adenine, Thymine, Guanine and Cytosine. The way these bases are strung together
creates a ‘code’ that helps provide instructions for how our body grows and functions. DNA is found
in every cell of our body– except red blood cells (no nucleus).
define genes
Genes are a segment of DNA. Our genes are the blueprint for our biology. They contain instructions for things like the shape of our nose and the size of our feet. It is estimated that we have approximately 25, 000 different genes in our body.
define chromosomes
a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
explain the relationship between chromosomes genes DNA
Chromosomes are structures made up of chromatin. Chromatin is the thread of DNA that gets condensed to form chromosomes.
Genes are the segments of DNA that code for proteins. Hence, each chromosome is made up of DNA and contains many genes because of segments of DNA.
explain why chromosomes can be sorted into pairs
Diploid organisms, like humans, carry two copies of the genome in each one of their cells. Having two copies of each chromosome, called homologous chromosomes, helps increase both the variety and stability of a species.
describe the structure of DNA
DNA is a double helical structure composed of nucleotides. The two helices are joined together by hydrogen bonds. The DNA also bears a sugar-phosphate backbone
how does the DNA structure produce genetic information for an organism?
Each molecule of DNA is a double helix formed from two complementary strands of nucleotides held together by hydrogen bonds between G-C and A-T base pairs. Duplication of genetic information occurs by the use of one DNA strand as a template for the formation of a complementary strand.
what is the difference between an allele, and a gene?
A gene is a unit of hereditary information. Except in some viruses, genes are made up of DNA, a complex molecule that codes genetic information for the transmission of inherited traits. Alleles are also genetic sequences, and they too code for the transmission of traits.
