Biology
Why are males more likely to show X-linked recessive traits than females?
Because they only have one X chromosome. Females have two, so if a sex linked trait is recessive, females have a spare that could potentially cover up that trait. But males don't, so regardless of what happens, it's going to show.
Define Allele
Different forms of the same gene
Where do Dna replications happen?
Dna replications takes place in the nucleus
Recall the number of chromosomes contained by each human egg or sperm
Each human egg or sperm contains 23 chromosomes
Define Gene and nucleotide
Gene- a section of DNA that carries the genetic code for a certain characteristic Nucleotide: phosphate group, nitrogen rich base and deoxyribose sugar make it up
Recessive
Genotype= rr only observed in this case
Define Nucleotides and Chromatid
Nucleotides- The building blocks of Dna Chromatid- One of the strands of a chromosome following replication
Meiosis
Produces gametes (haploid) and has half the number of chromosomes as the parent.
Define Recessive and Dominant
Recessive- The characteristic that remains hidden in the homozygous condition Dominant- The characteristic that is expressed in the homozygous condition
Define chromosome and sex-linked genes
Sex-linked genes- Genes present on the sex chromosomes. Chromosomes- thread like structures in the nucleus. Composed of DNA and proteins: contains the genetic information in the form of genes.
what is an enzyme?
Speeds up a reaction in this instance it's job is to unwind the bases strands. But it also helps bond the new pairs together.
The gametes of a fruit fly have 4 chromosomes. What is the diploid number for the fruit fly
The Diploid number is 8
Define sex chromosomes
The chromosomes that determine the sex of an individual. In humans they are x and y chromosomes.
Most cells in your body contain 2 of each type of chromosome (i.e they have 2N chromosomes). Recall the exception to this?
The exception to this is the Gametes
When will a person carry a recessive gene?
The person may carry it if they are heterozygous- Rr
What forms the upright parts of the twisted DNA ladder?
The phosphate units and the alternating sugar forms the upright parts of the ladder.
Where are chromosomes found?
They are found in the nucleus of most cells of your body
Female / male
FEMALE- XX MALE- XY
What is meant by the term "carrier"
A carrier is when they don't have the particular disease but they carry it and can pass it on to their children. The children may end up having that disease. They have a recessive Phenotype.
What is a complementary strand of DNA
A complementary strand is AGTACG the complementary on is TCATGC
What is a Gamete
A mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
Phenotype Genotype
Observable characteristics example: black hair Actual genetic information example: Rr
What do the letters A,C,T,G stand for in a DNA base sequence?
Adenine, Thymine, Guanine, cytosine
Define Autosome
All the chromosomes in a cell other than the sex chromosomes
Dominant
Characteristics that is observed when the geno-type is RR or Rr. it is observed in a heterozygous individual.
The phases in Mitosis
Interphase, Prophase, Metaphase, Anaphase, Telephase and cytokinesis
Mitosis
Produces daughter cells (identical copies) and for growth and repair
Define Replication and Genome
Replication- The process of making copies of DNA. Genome- The genetic information carried by a haploid set of chromosomes.
Heterozygous Homozygous
Rr RR or rr
Define Inheritance
The genetic characteristics transmitted from parent to offspring characteristics genes
Recall the number of chromosomes in cells after meiosis compared to the original cell
half
What do the letters DNA stand for
Deoxyribo Nucleic Acid
What is Diploid and Haploid
Diploid- The number of chromosomes in two sets or 2N Haploid- The number of chromosomes in gametes, one set or N
When is the sex of an individual determined?
When the egg is fertilized by the sperm
Where are chromosomes found? What are they made up of? How many do humans have in their body cells? How many chromosomes are in gametes?
which are found in the nucleus and contains our genetic information in the form of genes. Made up of DNA and Protein. Humans have 46 chromosomes in their body cells. 23 pairs. When the gametes join they form a cell called a zygote. Human sperm and eggs contain 23 chromosomes. Human zygotes contain 46 chromosomes. The type of cell division that produces gametes with half the normal chromosome number is called meiosis. They are coiled up pieces of Dna and protein.
