Genetics And Family History Flashcards
What is the location and function of DNA
Found in the nucleus of a cell
Carries genetic material
Structure of dna
Nucleotide are made of 4 bases
Adenine and thymine and guanine and cytosine
A-T C-G
Nucleotides are linked together via the phosphate to form the back bone of chain
A-T bonded with two hydrogen bonds C-G have 3 hydrogen bond between them
Replication process ¿
Happens each time a cell divides
The dna strands is unzipped or sepereated by a enzyme called helicase which is breaking the hydrogen bonds between the pairs
Enzymes primate starts the process of rebuilding the separated strands
Primases makes a small piece of RNA which is a primer- it tells the seperated strands to rebuild using the bases which match
What is RNA, structure and function and where are they found
It is nucleic acid present in all living cells similar structure to DNA but it’s most often single stranded
Has. Backbone made of alternating phosphates groups and the sugar ribose rather than deoxyribose found in DNA
ATTACHED TO EACH SUGUR IS ONE OF FOUR BASES adenine, uracil, and cytosine and guanine
Some rna invoked in regulating gene expression
Some viruses uses RNA as their genomic material
Found in cells nucleus, cytoplasm and organelles
What are chromosomes
Bundle of dna
Tightly coiled strand of dna around the histone
Histones are protein which give structure to the long strand of dna
How many chromosomes are their
46 chromosome with 23 homologous pairs
22 of the pairs are autonomous and the 23rd pair is sex determining usually xx or xy
Chromosomes carry different amounts of genetic material
Describe diploid cells
(Double)
All cells in the human body=diploid cell apart from sperm and egg cells.
They contain all the genetic material
23 pairs of chromosomes-22 pairs of autosomes and 1 pair of sex chromosomes.
They are produced from identical versions of themselves -mitosis
Reproducing identical versions of themselves is perfect as the body grows and repairs itself.
Describe haploid cells
Only haploid cell is sperm and egg cells
23 chromosomes but not pairs
Made by diploid cells via meiosis producing 4 non identical versions of themselves cell with only half of the genetic material
Each 4 produced haploid cells contains different set of genetic materials to the other 3
Shows why siblings are not identical to parents or each other
What is a gene
Section of DNA that codes for a particular protein
E.g gene for dimples
Humans are 99.9% identical remaining makes us different
20000-25000 genes in the human genome
Genes are made up of series of nucleotides bases in a chain from a few hundred to 2 million per gene
Genes further broken down to codons
Codons are smaller units
Codons are chains of 3 base grouping ATT, GCC, CGT
What are alleles
Different versions of the same gene
Individual inherits two alleles one from each biological parent. If two alleles are identical the homozygous if different then heterozygous.
Describe mutations
Alterations of bases in the genetic code are mutations
Protein produced is malformed
What is a phenotype
Observable physical properties of an organism
