Meosis, Genetics, Exam 4

What is a genome?

The entire set of genetic material in an organism

What is the basic difference between an autosome (somatic) chromosome and a sex chromosome?

Autosomes: not sex chromosomes

Sex chromosomes: X and Y

What is a homologous chromosome?

one of 2 paired chromosome one from each parent, carries genes for specific trait at same location

What is the difference between a diploid and a haploid?

Diploid is 2 sets and Haploid is 1 set

What are Gametes?

sex cells (sperm and egg)

Are somatic cells haploid or diploid?

diploid

What is the basic purpose of Meiosis 1?

to reduce the chromosome number by half (from diploid to haploid) and introduce genetic diversity through crossing over

What is the basic purpose of Meiosis 2?

it serves to separate the sister chromatids, resulting in four unique haploid daughter cells that go on to become gametes

What is crossing over and where does it take place?

exchange of corresponding segments between two homologous chromosomes... Takes place is the chiasma

At what stage do the homologous chromosomes randomly line up in the center of the cell?

Metaphase 1

Please know that these are the two main sources of genetic variability in the offspring (that occur during meiosis)

crossing over and the independent assortment of chromosomes.

3 sources of genetic variability?

Independent orientation of chromosomes at metaphase I, random fertilization, and crossing over during prophase I of meiosis

Stage of Meiosis 1?

Prophase I

Stage of Meiosis 1?

Metaphase I

Stage of Meiosis 1?

Anaphase I

Stage of Meiosis 1?

Telephase I and Cytokinesis

Stages of Meiosis 2?

prophase 2, metaphase 2, anaphase 2, telophase 2

How many daughter cells are formed at the end of Meiosis I and II?

I has 2, II has 4

What is a karyotype?

a photographic inventory of an individual's chromosomes

Who is XX and who is XY?

Women are XX, Men are XY

Why does the father determine the sex of a baby?

Because males have X and Y chromosomes while females only have X so depending on if the male gives an X or a Y chromosome will determine if its a boy or a girl.

What is trisomy 21?

down syndrome, extra chromosome 21

How does nondisjunction occur?

chromosomes fail to separate at the centromere during Meiosis 1 or Meiosis 2

Characteristics of Down Syndrome?

Round face, wide-set eyes, intellectual disability.

Characteristics of Klinefelter syndrome?

XXY, Female characteristics, wider hips, and a shortage of testosterone

characteristics of turner syndrome

Wide neck and short, and unable to have children.

Which disorder is this?

Down Syndrome

What disorder is this?

Turner Syndrome

What disorder is this?

Klinefelter Syndrome, XXY

Down Syndrome

Turner Syndrome, XO

Deletion?

A piece of the chromosome is missing

Duplication?

change to a chromosome in which part of the chromosome is repeated

Inversion?

re-ordering of genes on a chromosome

Reciprocal Translocation?

segments of two nonhomologous chromosomes swap locations with each other

Who is the father of genetics?

Gregor Mendel

What did Gregor Mendel experiment with?

pea plants

Trait?

any characteristic that can be passed from parent to offspring

Homologous pairs?

a pair of chromosomes, 1 materanal and 1 paternal

Alleles?

Different forms of a gene

Homozygous?

Purebred XX

Heterozygous?

Hybrid Xx

Dominant?

An allele that is always expressed is represented by the capital (L) letter

Recessive?

An allele that is less frequent and is represented by a lowercase letter

Genotype?

An organism's genetic makeup, or allele combinations.

Phenotype?

An organism's physical appearance, or visible traits.

Monohybrid crosses?

crosses that examine the inheritance of only one specific trait

What is a pedigree?

a chart that tracks which members of a family have a particular trait

Why would a pedigree be useful for a family?

Serves as a genetic family tree that can show traces of disease and traits

autosomal recessive

inheritance pattern of a recessive allele on an autosome

autosomal dominant

distinct generational patterns

What is the percentage chance of inheritance of the disease?

In Recessive its 25% if both have it, and Dominant, if even one person has it its 50%

Is sickle cell dominant or recessive?

recessive

Is cystic fibrosis dominant or recessive?

recessive

Is Huntington's disease dominant or recessive?

dominant

How are autosomal diseases transferred?

Through generations

Sickle Cell

Cystic Fibrosis

Huntingtons

What is codominance?

when both alleles contribute to the phenotype

Which blood type shows codominance?

Type AB

X-linked disorders?

Genetic conditions that result from mutations to genes on the X chromosome. They are almost always expressed in males, who have only one copy of the X chromosome; in females, the second X chromosome containing the normally functioning allele protects them from developing X-linked disorders.

Color blindness and hemophilia are examples of?

sex-linked disorders/traits

Reciprocal Translocation links to what?

-links to cancers, possible tie to schizophrenia.

What is an example of Inversion?

Humans evolving from chimpanzees.

Duplication disorders

Edwards and Patau syndromes.

Deletion disorders-

Cru di chat and Wolf-Hirschhorn Syndromes

DELETION ON CHROMOSOME 5-CRI-DU-CHAT SYNDROME

DELETION ON CHROMOSOME 4-WOLF-HIRSCHHORN SYNDROME

DUPLICATION-EDWARD’S SYNDROME (TRISOMY 18)

DUPLICATION-PATAU’S SYNDROME (TRISOMY 13)