Biology summary ch5
5.1 Pass it on!
Inherited= receiving a genetic characteristic transmitted by a parent.
Genotype= complete set of all inherited characteristics. (what you can’t see)
Phenotype= set of inherited characteristics that are actually expressed. (what you
can see)
Phenotype = genotype + environmental factors.
Chromosome= structure inside the nucleus that contain inherited stuff.
There are 46 chromosomes inside a fertilised egg cell. All of the cells that will grow
will each have one set of the same 46 chromosomes.
Karyotype= a photo of all chromosomes in one cell grouped together and arranged.
Homologous pairs= 2 chromosomes that match each other in the genes they contain.
An egg cell and sperm cell only have 23 chromosomes each instead of 46 like other
cells.
When and egg cell and sperm cell fuse, their chromosomes form homologous pairs.
5.2 What are the chances?
Humans have 23 pairs of chromosomes, one of these pairs is a pair of sex
chromosomes and the other 22 are called autosomes.
Sex chromosome= one of the 2 special chromosomes. The x and y combination
determines the gender.
Autosome= one of the 44 regular (non-sex) chromosomes in a human.
Boy= 2 x 22 autosomes + X + Y = 46 chromosomes
Girl= 2 x 22 autosomes + X + X = 46 chromosomes
A sperm cell= Type 1: 22 autosomes + X = 23 chromosomes or,
Type 2: 22 autosomes + Y = 23 chromosomes.
An egg cell= 22 autosomes + X = 23 chromosomes. (only possibility)
Male is an X and Y, Female is 2 X.
5.3 DNA and genes
, DNA= the hereditary material in organisms.
DNA is made up of small units called nucleotides.
Nucleotides= consists of 3 parts; the base (with the info), a phosphate and a sugar.
Phosphate and the sugar are sort of the backbone which connects.
There are 4 different types of nucleotides. All have the same sugar and phosphate
but a different base. There are 4 bases in total; guanine, adenine, thymine and
cytosine. Abbreviated with the letters G, A, T and C. Nucleotides line up and connect
one half of a DNA strand, two nucleotides strands make a double DNA strand. C
always binds to G and A always binds to T on the opposite strand. This is called baise
pairing.
Base-pairing= the organisation of bases in opposite strands od DNA: A – T and G – C.
Gene= a section of DNA that has the complete code for a single protein.
Cell -> Nucleus -> Chromosome -> DNA -> Genes -> Nucleotides -> Base, Phosphate,
Sugar.
5.4 Inheritance
Alleles= different forms of the same gene.
A stands for brown eyes, a stands for blue eyes.
AA= brown eyes Aa= brown eyes aa= blue eyes
Phenotype= brown eyes Genotype= AA
Dominant= the allele that is expressed. Always a capital letter
Recessive= the allele that isn’t expressed or masked by the other allele. Always a
small letter
Carrier= having a dominant, expressed allele and a recessive, masked allele.
If you are homozygous for eye colour you have AA or aa. If you are heterozygous for
eye colour you have Aa.
F1= first generation of offspring (children), F2 second generation (grandchildren).
Punnet square= a table for determining genetic offspring.
Sperm (B) Sperm (B) F1 Sperm (B) Sperm (b)
Egg cell (b) Bb (F1) Bb (F1) Egg cell (B) Bb (F2) Bb (F2)
Egg cell (b) Bb (F1) Bb (F1) Egg cell (b) Bb (F2) bb (F2)
Probability= the chance that something will happen.
5.5 When genes change
Mutation= a change in a chromosome or gene.
5.1 Pass it on!
Inherited= receiving a genetic characteristic transmitted by a parent.
Genotype= complete set of all inherited characteristics. (what you can’t see)
Phenotype= set of inherited characteristics that are actually expressed. (what you
can see)
Phenotype = genotype + environmental factors.
Chromosome= structure inside the nucleus that contain inherited stuff.
There are 46 chromosomes inside a fertilised egg cell. All of the cells that will grow
will each have one set of the same 46 chromosomes.
Karyotype= a photo of all chromosomes in one cell grouped together and arranged.
Homologous pairs= 2 chromosomes that match each other in the genes they contain.
An egg cell and sperm cell only have 23 chromosomes each instead of 46 like other
cells.
When and egg cell and sperm cell fuse, their chromosomes form homologous pairs.
5.2 What are the chances?
Humans have 23 pairs of chromosomes, one of these pairs is a pair of sex
chromosomes and the other 22 are called autosomes.
Sex chromosome= one of the 2 special chromosomes. The x and y combination
determines the gender.
Autosome= one of the 44 regular (non-sex) chromosomes in a human.
Boy= 2 x 22 autosomes + X + Y = 46 chromosomes
Girl= 2 x 22 autosomes + X + X = 46 chromosomes
A sperm cell= Type 1: 22 autosomes + X = 23 chromosomes or,
Type 2: 22 autosomes + Y = 23 chromosomes.
An egg cell= 22 autosomes + X = 23 chromosomes. (only possibility)
Male is an X and Y, Female is 2 X.
5.3 DNA and genes
, DNA= the hereditary material in organisms.
DNA is made up of small units called nucleotides.
Nucleotides= consists of 3 parts; the base (with the info), a phosphate and a sugar.
Phosphate and the sugar are sort of the backbone which connects.
There are 4 different types of nucleotides. All have the same sugar and phosphate
but a different base. There are 4 bases in total; guanine, adenine, thymine and
cytosine. Abbreviated with the letters G, A, T and C. Nucleotides line up and connect
one half of a DNA strand, two nucleotides strands make a double DNA strand. C
always binds to G and A always binds to T on the opposite strand. This is called baise
pairing.
Base-pairing= the organisation of bases in opposite strands od DNA: A – T and G – C.
Gene= a section of DNA that has the complete code for a single protein.
Cell -> Nucleus -> Chromosome -> DNA -> Genes -> Nucleotides -> Base, Phosphate,
Sugar.
5.4 Inheritance
Alleles= different forms of the same gene.
A stands for brown eyes, a stands for blue eyes.
AA= brown eyes Aa= brown eyes aa= blue eyes
Phenotype= brown eyes Genotype= AA
Dominant= the allele that is expressed. Always a capital letter
Recessive= the allele that isn’t expressed or masked by the other allele. Always a
small letter
Carrier= having a dominant, expressed allele and a recessive, masked allele.
If you are homozygous for eye colour you have AA or aa. If you are heterozygous for
eye colour you have Aa.
F1= first generation of offspring (children), F2 second generation (grandchildren).
Punnet square= a table for determining genetic offspring.
Sperm (B) Sperm (B) F1 Sperm (B) Sperm (b)
Egg cell (b) Bb (F1) Bb (F1) Egg cell (B) Bb (F2) Bb (F2)
Egg cell (b) Bb (F1) Bb (F1) Egg cell (b) Bb (F2) bb (F2)
Probability= the chance that something will happen.
5.5 When genes change
Mutation= a change in a chromosome or gene.
