Genetics Flashcards
What is a genome
All the genetic material in a cell
What is a chromatin
The genetic material of a cell consisting of DNA, proteins and some RNA
How many chromosomes does a human cell have
46
A cell with 23 paired chromosomes is called what
A diploid
What is a haploid
Gametes (spermatozoa and ova) with only half of the normal complement, i.e. 23 chromosomes instead of 46.
What are chromosomes that belong to the same pair called
Homologous chromosomes
What is a karyotype
The complete set of chromosomes from a cell
What is a chromosome
A long molecule of DNA that is coiled together with several proteins
What are the first 22 pairs of chromosomes collectively known as?
Autosomes
What are the pair 23 chromosomes known as and what do they determine.
They are sex chromosomes are determine the individuals gender
What gender carries the Y chromosome
Male
What gender is a child with 2 X chromosomes known as
Female
What are genes
Genes are the cell’s hereditary units that control cellular structure and direct cellular activities.
How many genes are there is a single chromosome
25000-30000
What DNA made up of
Two chains of nucleotides
Nucleotides consist of 3 subunits, what are these?
A sugar
A phosphate group
A nitrogenous base
There are A,T,C,G binds in a DNA (in the middle) that bind together? What do the A binds bind to and ETC
A binds to T
C binds to G
What are do the A,T,C,G, binds stand for
Adenine
Guanine
Thymine
Cytosine
What maintain the 3D coiled shape of DNA
Histones
What does mutation mean
Mutation means an inheritable alteration in the normal genetic make-up of a cell.
What are some external factors that can cause mutation
X-Rays
Ultraviolet rays
Exposure to certain chemicals
Mutation facts revision card
Most mutations are immediately repaired by enzymes present in the cell nucleus, and therefore cause no permanent problems.
However, sometimes the mutation is lethal, because it disrupts some essential cellular functions, causing cell death.
Often, the mutated cell is detected by immune cells and destroyed because it is abnormal.
Some mutations do not kill the cell but instead alter its function in a way that can cause disease, what is an example of this.
Cancer
How many amino acids are the building block of human proteins.
About 20 different amino acids
What is mRNA
As the cell’s DNA is too big to leave the nucleus, an intermediary molecule is needed to carry the genetic instructions from the nucleus to the ribosomes in the cytoplasm, where proteins are made. This is called messenger (mRNA)
What is gene expression
a gene’s DNA is used as a template for synthesis of a specific protein.
What are the 2 steps of protein synthesis
The protein synthesis process consists of 2 steps: transcription and translation.
What is the transcription stage of protein synthesis
The information encoded in a specific region of DNA is transcribed (copied) to produce a specific molecule of RNA (ribonucleic acid).
What is the translation stage of protein synthesis
During translation, the RNA attaches to a ribosome, where the information contained in RNA is translated into a corresponding sequence of amino acids to form a new protein molecule
What is meiosis
The division of 23 chromosomes in each sex chromosome coming together in fertilisation, creating a diploid amount of chromosomes.
How many divisions are there in mitosis
1
How many divisions are there in meiosis
2
What is a dominant allele?
A dominant allele is an allele that dominates or masks the presence of another allele and is fully expressed, and the trait expressed is called a dominant trait.
What is a recessive allele?
The allele whose presence is completely masked is said to be a recessive allele, and the trait it controls is called a recessive trait.
What table is used to summarise all the alleles?
Punnet squares
How many genes does the Y chromosome have
about 200
How many genes does the X chromosome have
about 2000
When is sex of the baby determined
Sex is determined at the time of fertilization by the presence or absence of a Y chromosome in the sperm.
Thus, an individual’s sex is determined by the father’s chromosomes
