Genetics Questions

where are chromosomes found in a cell?

in the nucleus.

what are homologous chromosomes?

pairs of chromosomes similar in size, location & banding pattern.

how many chromosomes do humans have?

46 chromosomes (23 pairs).

what are sex chromosomes in females and males?

females: XX

males: XY

what is a karyotype?

a picture of all chromosomes arranged from largest to smallest in pairs.

what can a karyotype show besides chromosome number?

the sex of an individual and chromosomal abnormalities.

what are the parts of a DNA nucleotide?

deoxyribose sugar, phosphate group & nitrogen base.

Which Nitrogen bases pair together?

A (adenine) pairs with T (thymine)

C (cytosine) pairs with G (guanine )

what does a codon code for?

a specific amino acid.

what is the function of mitosis?

to produce two genetically identical diploid daughter cells for growth and repair.

what is the outcome of meiosis?

four genetically different haploid gametes.

define mutation.

a change in the DNA sequence.

name two types of mutations.

point mutation & frame shift mutations.

what is a chromosomal mutation?

a change in chromosome structure, affecting many genes.

what are 5 examples of chromosome mutations?

duplication, deletion, inversion, insertion & translocation.

what is the difference between dominant and recessive traits?

dominant traits require 1 allele to show.

recessive traits require 2 alleles to show.

what is co-dominance?

both alleles are fully expressed (eg. AB blood type).

what is incomplete dominance?

heterozygous individuals show a blend of both sides.

what is a carrier?

someone who is heterozygous for a recessive trait who does not show it but can pass it on.

how many pairs of autosomes are in humans?

22 pairs

what are gametes?

mature haploid sex cells (sperm or egg).

what is the total number of chromosome pairs in a human?

23 pairs.

what type of cells undergo mitosis?

body cells (somatic cells).

what type of cells undergo meiosis?

gametes (sex cells).

the difference between haploid and diploid cells?

diploid cells have 2 sets of chromosomes (2n)

haploid cells have one set of chromosomes (n)

what is an example of a genetic disorder cause by extra chromosomes?

down syndrome (trisomy 21)

which syndrome results from and extra X chromosome in males?

klingeltet syndrome (XXY)

what syndrome results from having only one X chromosome?

turner syndrome (XO)

what does frame shift mutation mean?

inceptions or deletions that shift the reading of codons.

what happens during DNA replication?

DNA makes an extra copy of itself before cell division.

how do multiple alleles affect blood type inheritance?

more than two alleles ( IA, IB, i ) determine blood types.

what blood type is an example of co dominance?

AB blood type.

what does inversion mean in chromosomal mutations?

a chromosome segment breaks off, flips and reattaches.

what are autosomes?

chromosomes other than sex cells.

what is genetic variation and why is it important?

differences in DNA sequences; it helps populations adapt and survive

how is a mutation beneficial?

it improves survival or reproduction chances.