Genetics

Science sem 1

Genetics is the…

study of heredity

Heredity is the….

study of biological inheritance

What is biological inheritance?

The passing down of biological traits

What are genes?

genes instruct cells to build proteins that determine how we look and function.

what are codones?

codones code for a piece of protein called amino acid

What is meosis?

when cells divide to form sex cells (sperm/egg cells)
the copies made are not identical to the orginal cells.

cell division process that results in new cells with half the number of chromosomes of the original cell

how many individual chromosomes are left after meosis

23 individual chromosomes are left

What is mitosis?

this is when one body cell divides to make 2 identical copies of itself

cell division process that results in new genetically identical cells with the same number of chromosomes as the original cell

Mitosis is needed ______ for ____ and _______.

mitosis is needed everyday for repair and growth.

What are chromosomes?

DNA that is wrapped around proteins to form a bundle

packed tightly so long strands of DNA can fit into a nucleus

How many chromosomes do humans typically have?

46 chromosomes per body cell.

What are somatic cells?

body cells

what are germline cells?

cells that divide into sperm and egg cells during meiosis

what are somatic mutations?

mutations in body cells that are not passed offspring.

what is an example of a somatic mutation?

mutations in skin cells can cause skin cancer but are not passed on.

what is klinefelter disease?

when a male is born with an extra X chromosome.
occurs as random genetic error

what are chromosomal mutations?

involves changes in the structure and number of chromosomes.

What is a karyotype?

the complete set of chromosomes in an individual

How are karyotypes organised?

grouped in pairs of homologous chromosomes
arranged in length, banding pattern, centromere position, satellite endings

What are homologous chromosomes

a pair of chromosomes inherited from each parent

what are sex chromosomes

the pair of chromosomes which will determine the gender of a baby

determine what gender a baby will be with the sex chromosomes XX

female

determine what gender a baby will be with the sex chromosomes XY

male

What are autosomes?

chromosomes that are not sex chromosomes

What is nondisjunction?

when chromosomes do not seperate evenly

what is trisomy?

having an extra copy of a chromosome.

What is monosomy

term for having only one copy of a chromosome

what is an example of monosomy?

Turner syndrome (XO)

What is a genotype?

the genetic makeup of an organsim
written in letters

e.g: Hh

What is phenotype

the appearance of an organism

what it physically looks like

written in words.

what is an allele

one form of a gene that has 2 or more alternative genes

Give 2 examples of alleles

skin colour, hair colour

What does heterozygous

Genotype with 2 different alleles
hetero = different

E.g: Hh

Homozygous what is it?

genotype has 2 identical alleles

What is a dominant gene?

dominant a trait (phenotype)

that requires only one allele to

be present for its expression in a

heterozygote

what is a recessive gene?

a trait (phenotype)

that will only be expressed in

the absence of the allele for the

dominant trait

What are diploid cells?

cells that are genetically identical
results from mitosis

What is chromatid?

one identical half of a replicated chromosome

what is a centromere?

the section of chromosome that holds together two sister chromosomes

What are daughter cells?

what is a zygote?

zygote a cell formed by the fusion of male and female reproductive cells

diploid

the possession of two copies of each chromosome in a cell

(appear as 23 pairs in each cell-typically with pair)

what are daughter cells?

cells that are formed after cell division

What are gametes?

reproductive or sex cells.

what are nucleotides?

chemical units that contain specific bases that form DNA code.

Building blocks of DNA

what are nucleotides made up of?

within a nucleotide there is a: Phosphate group
Pentose sugar
Nitrogenous base

What is the rule of complementary pairing?

A → T
G → C

What does A, T, G, C stand for?

Adenine
Thymine
Guanine

Cytosine

what does DNA provide for and organisim?

DNA provides chemical instructions about how to build an organsim.

What are the codones

A,T,G,C bases

What are the different types of mutations?

Deletion
Addition/Insertion
Substitution

Point mutations

What is deletion mutations?

one or more codon bases are deleted

What is addition mutations

an additional codon is added in to a gene

what is substitution mutations

Occurs when one nucleotide swaps for another

what is an amino acid

an organic compound that forms the building blocks of proteins

what is a silent mutation?

when the change in DNA code is actually the smae amino acid.

what is an example of a silent mutation?

sickle cell anaemia.

what are point mutations

when there is a change to one of the nitrogenous bases (A,T,G,C)

where are nucleotides found?

Make up the DNA

a sugar, base phosphate make up…

one nucleotide.

protein, amino acid, DNA, nucleotides,

Differnce between gametes and sex chromosomes

gametes = sperm and egg

sex chromosomes = 23 pair that determine gender of person

Difference between genes and chromosomes

difference between gene and DNA

what is klinefelter’s?

a chromosomal disorder that is where there is an extra X chromosome in a male

What are the letters of of mitosis?

PMAT

what are the names for the phases of mitosis?

prophases
Metaphase (middle)

Anaphases (away)
telophase (begin to seperate)

what is the function of a punnet square?

Used to predict outcome of a genetic cross.

Shows which allele for a certain trait are present in the gametes of each parent.
Then shows possible ways these can be combined.

List the 4 types of domiance

Complete dominance
Incomplete/partial dominance

Codominance

Sex-linked

what is complete dominance?

only dominant allele shows phenotype

What is incomplete/partial domiance?

both dominant alleles are able to be express themselves (partially)
Red flower + White flower = PINK flower

what is co-domiance?

both dominant alleles express themselves equally
Human blood groups= AB, Cow hair colour.

What are sex linked dominance?

trait is due to allele on X chromosome.
more in males than females,

females can be carriers

What are the 4 inheritance pattererns.

Autosomal dominant

autosomal recessive

x-linked dominant

X-linked recessive

Each affected person Has an affected parent: occurs in every generation

Autosomal dominant

Both parents of an affected person are carries; not typically in every generation

Autosomal recessive

Female more frequently affected as all daughter & no sons of an affected man will be affected

can have affected male & females in same generation

X linked dominant

Males more frequently affected

Affected males often present in each generation

X-linked recessive

X-linked recessive

Both parents of an affected person are carries; not typically in every generation

Autosomal dominant

Each affected person Has an affected parent: occurs in every generation

X-linked recessive

Males more frequently affected

Affected male often present in each g

X linked

What are DNA triplets

DNA triplets code for a particular amino acid