Biology Flashcards
What are the building blocks of DNA?
a molecule of DNA is made up of millions of tiny subunits called Nucleotides (monomers) mono=1
What are the components of a nucleotide?
Each nucleotide consists of:
1. Phosphate group
2. Pentose sugar
3. Nitrogenous base
What components form the backbone?
The sugar and phosphate form the backbone of the DNA molecule.
What components form the rungs?
the nitrogenous bases form the rungs
What are the four types of nitrogenous bases?
(A)- Adenine
(T)- Thymine
(C)- Cytosine
(G)- Guanine
What is complementary base pairing?
Complementary base pairing is each base will only bond with one other specific base eg.
A-T C-G
Why does DNA have a double helix?
The rules and components allow DNA to form a double helix
Where is DNA found in the cell?
In the nucleus, it contains the genetic information (DNA)
How is DNA organised in the nucleus?
Organised into units called genes, genes are found on chromosomes
What is a gene?
A segment of DNA that codes for a particular protein
How many pairs of chromosomes do humans have?
Human body cells have 23 pairs of chromosomes which means 46 in total
What does diploid mean?
A pair of chromosomes in somatic cells
What is a somatic cell?
cells of the body except sex cells
What are gametes?
Reproduction of sex cells ( sperm/ova)
What does haploid mean?
Possession of one copy of each chromosome in a cell
( 46/2=23)
What sex chromosomes do females have
XX- FEMALE
What sex chromosomes do males have?
XY-MALE
What is an Autosome?
Any chromosomes not involved in sex determination
What is a sex chromosome?
The chromosomes that determines an individual’s sex
What is an Allele?
It is a different version/form of a gene eg. eye colour/hair
What is the difference between a gene and an allele?
Gene specifies trait, allele specifies form genes take.
What are dominant alleles?
These alleles will always be expressed when they are present.
What are Recessive alleles?
These alleles are expressed only when they are present.
What is a Genotype?
The alleles that a person has
eg. B- dominant b- recessive
What is a phenotype?
The trait that is seen
example- brown eyes
What does homozygous mean?
The same
What does heterozygous mean?
Different
What is a pedigree chart?
It is a chart of the genetic history of a family over several; generations
symbols meanings
affected/
What are the symbols?
Female- circle
Male- square
what is translation?
the process by which mRNA is ‘read’ to produce a strand protein chain
what does tRNA stand for?
transfer RNA
where does translation happen?
they carry specific, individual, amino acids
