Genetics Y10

Genetics class with Ms Power

DNA

deoxyribonucleic acid is the genetic code that is unique to every person,

Structure of DNA

consists of 2 sugar phosphate backbones twisted in a double stranded helix,

DNA base pairings

Adenine(a) pairs with thymine, cytosine (C) pairs with guanine (g)

Chromosomes

thread like structures inside the nucleus that contain DNA

How do chromosomes become visible

Chromosomes become visible by shortening and thickening when a cell is ready to replicate

Human Somatic cell

all cells that contain diploid number, cell that contains 46 chromosomes (22 pairs of autosomes), and 2 sex chromosomes

X and Y Size

X chromosome is bigger than Y chromosomes

Male Chromosomes

X Y

Female chromosomes

2 X chromosomes XX

Diploid Number

the total number of pairs in a somatic cell (23 pairs or 46)

Example of somatic cell

Body cells like nerve cells

Haploid Number

the number of chromosomes in a gamete/ sex cell (half diploid number 23)

Example of gamete

sex cells

Karyotype

image that shows the number and appearance of a set of chromosomes in a somatic cell

Gene

parts of DNA that have instructions for a particular protein

Alleles

different versions of the same gene, for example one allele for green eyes the other for brown

Inheritence

The passing of DNA from parent to offspring

2 Types of protein synthesis

Transcription and translation

Transcription

parts of DNA blueprint are read and a complementary mRNA strand is created in nucleus

Translation

when mRMA is read and produces an amino acid created 3 bases in ribosomes

mRNA

single stranded nucleic acid that carries instructions from dna

mRNA base pairings

• Adenine (A) pairs with Uracil (U).

• Cytosine (C) pairs with Guanine (G).

Journey of mRNA

travels from the nucleus into the cytoplasm to ribosomes for translation

Protein

A molecule made from a chain of amino acids used to build and repair muscle

Mitosis

the process where DNA is replicated in somatic cells resulting in two identical somatic cells to parent cells, occurs in somatic cells

Meiosis

a type of cell division that produces gametes, occurs in germ cells has 2 rounds of cell division, creating four haploid daughter cells from a single diploid parent cell,

Haploid number

have half the number of chromosomes of a somatic cell

(half diploid number)

Fertilization

involves a male and a female gamete (each haploid) combining, resulting in a diploid cell with DNA from both parents.

Genotype

a persons unique sequence of DNA inherited from parents, ex Bb

Phenotype

Phenotype is the characteristic that results from the expression of an organism's genotype ex, blue eyes, dependent on genotype and environment

Homozygous

both alleles are the same

Heterogeneous

when alleles are different

Puneet square

square is used to determine and display the chances of an offspring genotype considering the parental genotypes.

Pedigree

 chart is used to show the inheritance pattern in a family over several generations

Rules for pedigree chart

 generations from oldest to most recent (partners joined by straight lines), females indicated by circles, males by squares, and those with the phenotype shaded. Siblings are from youngest to oldest, a line in between is marriage, line horizontal means child

Mutation

a change in a DNA, can cause big effects to health and can also have no effect, known as silent mutation.

Dominant Trait

a trait that will be expressed if at least one allele is present in preference to others

Recessive trait

a trait that will only be expressed if both alleles are present

Co- dominance

when two alleles are both expressed in an offspring, AB blood

Mutagen

an agent or factor that causes a mutation

Increased knowledge of genetics is influencing our society and is resulting in changes to our lives and beliefs.

Increased knowledge of genetics is influencing our society and is resulting in changes to our lives and beliefs.

Cell structure from smallest to largest

Nucleotide, DNA strand, gene, chromosomes, nucleus, Cell

Nucleotide

fundamental building blocks of DNA and RNA