LS4001 Genes, Cells and Tissues - Genes and Inheritance

What does phenotype mean?

Physical appearance of a genetic trait

What is a mutation?

any change in the DNA sequence

What is a gene?

segment of DNA responsible for a trait

What is an allele?

an alternative version of a gene

What is genetic inheritance?

The way in which a trait is passed down generationally

Genes inhereited through mitosis/meosis?

Meosis!

What is the difference between a chromosone and a chromatid?

Chromosone is a fixed meal set of genes, a chomatid is how many copies of that fixed set of info there are

STAGE 1 ONE MEOSIS

PROPHASE (5)
the genetic information from the nucleus is condensed into chromosomes. The nuclear envelope breaks. The rest happens in the cytoplasm of the cell. Homogenous chromosones (similar in size shape and function [eye color etc clothes]) pair up (one from Mum, one from Dad). They then cross_over for genetic variation.

METAPHASE.
Recombinant homogeneous chromosomes line up two-by-two in the middle of the cell thanks to spindle fibers.

ANAPHASE.
The spindle fibers pull each of the homogolous pairs to opposite sides of the cell.

TELOPHASE.
New nuclear envelopes form one each side.

CYTOKENESIS.
Eponymous

STAGE 2 MEOSIS, NORMAL MITOSIS

PROPHASE (2)
Genetic information condenses into chromosomes. Nuclear envelope dissolves

METAPHASE.
Chromosomes line up in the middle of the cell attached at spindle fibers at centromeres

ANAPHASE.
The spindle fibers pull the chromosomes in half, to opposite size of the cell

TELOPHASE.
New nuclear envelopes form one each side.

CYTOKENESIS.
Eponymous

starting and finishing genetic material STAGE 1 MEOSIS

starts with 92 chromtids (2 sets of info)

ends with 46 genetically variant chromatids (One full set of info)

starting and finishing genetic material STAGE 2 MEOSIS

starts with 46 genetically variant chromatids (One full set of info)

ends with two haploid cells (with info from both parents)

starting and finishing genetic material - MITOSIS

starts with 92 identical chromatids (two sets of the same info)

ends with 2 identical full sets of the info, in separate cells.

Humans are diploid/somatic?

diploid, one set of info mum, one from dad, summimg to two, hence diploid

What is a dominant allele?

an allele that is fully expressed in the phenotype of a heterozygote

What is a reccesive allele?

an allele that will not show unless both alleles are reccesive

What does homozygous mean?

Possesing both homozygous, or both reccessive

What does heterozygous mean?

one dominant and one recessive allele

What does diploid mean?

containing two complete sets of chromosomes, one from each parent.

What does somatic mean?

only onse set of chromosones

What does haploid mean?

having a single set of unpaired chromosomes (gametes)

What is a genotype?

genetic makeup of an organism

Mendel's Peas

What is incomplete dominance?

when one allele is not completely dominant over the other leading to a blending of traits. (Red+White=Pink)

What is codominance?

Bpth alleles are equally dominant

What does autosome mean?

Any chromosome that is not a sex chromosome

how many autosome pairs of chromosones in us? how many sex chromosone pairs?

22 autosome pairs of chromosones. 1 pair of sex chromosones.

What is sex linkage?

genes that are located on either the X or Y chromosome

What is a gene pool?

the sum total of all variations of this gene possesed by a specific species at a specific time

What is genotype frequency?

number of individuals with this genotype / total number of individuals in population

What is allele frequency?

number of individuals with this allele / total number of alleles of this gene

What does the Hardy-Weinberg principle assume? So what does it mean if the results deviate from the equation?

Assumes the opposite of Deviations which are:
-genetic drift
-bottle neck effect
-natural selection
-mutations
-migration

What is the Hardy-Weinberg equation?

p^2 + 2pq + q^2 = 1

Genes travel on _____________?

Chromosones

What is crossing over?

the exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring.

What is independent assortment?

Random distribution of homologous chromosomes!!!!

What are linked genes?

genes on the same chromosome

What are unlinked genes?

genes on different chromosomes

What is a genetic cross-test?

A test used t determine the genotype of an individual, where they could be homozygous dominant, or heterozygous. The indivual is bred with a homzygous reccesive individual, and their offspring are observed

What is the cross-test result for a homozygous dominant individual?

All of the offspring are are dominant.

What is the cross-test result for a heterzyous individual?

50% of the offpring are dominant, 50% of the offpring are reccesive

How many genes were used in the cross-test used for the discovery of gene linkage

Two different genes

How are the distance between genes and frequency of recombinance related.

each estra map unit if ditnce between two genes, increases thise genes' chance(FREQUENCY) of recombinance by 1%