Genetics (BIOL 2153 Larkin) Test #1

the phenotype is the characteristics of an organism which comes from the genotype (inhertited traits) and the environment.

How do genotype and environment contribute to phenotype?

fig 1.4

simplified structure of DNA

to preserve the sequence of bases

why is base pairing important for the replication of DNA?

Three nucleotides encode an amino acid.

How does the sequence of bases code for a sequence of amino acids in a protein (Fig. 1.7)?

The process by which genes affect the

phenotype.

Converts sequence of nucleotides to

sequence of amino acids in a protein,

via transcription and translation.

What is gene expression?

copying a gene's DNA sequence to make an RNA molecule

transcription

After transcription, the synthesis of a protein from RNA. process of going from language of nucleotides to language of acids.

translation

Changes in the DNA sequence of a

gene (mutations) change the sequence

of the encoded protein.

Therefore, mutations can alter protein

structure and function.

How does a change in DNA sequence (mutation) result in a change in protein sequence (Fig. 1.9)?

mutations can alter protein

structure and function.

How can a change in DNA sequence affect the phenotype?

Nucleus, mitochondria, chloroplast

Where is DNA found?

Purpose is to preserve chromosome number.

Stages:

Prophase,Metaphase, Anaphase, Telophase

mitosis

Purpose is to create haploid gametes, and to create new genotype combinations.

Stages: Prophase I, Metaphase I, Anaphase I, Telophase I. Followed by Prophase II, Metaphase II, Anaphase II, Telophase II.

meiosis

uracil, thymine

In RNA, the base ______ is used in the place of ______ used in DNA

the specialized DNA sequence of a chromosome that links a pair of sister chromatids

centromere

protective "caps" on the tips of chromosomes

telomere

G1, S, G2, mitosis, cytokinesis

The Mitotic Cell Cycle

occurs during meiosis where homologous chromosomes pair with their counterparts and remain bound due to the exchange of genetic information

synapsis

The synaptonemal complex (SC) is a protein structure that forms between homologous chromosomes (two pairs of sister chromatids) during meiosis and is thought to mediate chromosome pairing

synaptonemal complex

indicate where

chromosomes have

exchanged genetic

material.

chiasmata

Punnett Square & dominance aka genetics

Mendel

evolution. inheritance is carried by particles; first to realized that blending inheritance wasn't compatible with evolution by natural selection

Darwin

Student of T.H. Morgan; nondiss

Calvin bridges

Rediscovered Mendel's work

Correns

Rediscovered Mendel's work

hugo de vires

Rediscovered Mendel's work

Tschermak

discovered all chromosomes are needed for growth and function of organisms

Boveri

cancer

janet rowland

observed chromosomes in meiosis

Sutton

First to use the fruit fly Drosophila melanogaster as a research organism for genetics

T.H. morgan

X chromosome inactivation hypothesis

Mary lyon

1/4

What is probability siblings will have same HLA

Mendel's law of independent assortment states that the alleles of two (or more) different genes get sorted into gametes independently of one another.

independent assortment

Only one meiotic

product develops,

but it gets most of

cytoplasm.

oogenesis

All four meiotic

products develop,

all lose most of

cytoplasm.

spermatogenesis

A or a

gamete

AA or Aa

genotypes

partial loss-of-function alleles. They make an incompletely functioning product

hyomorph

alleles that produce more of the same active product

hypermorph

complete loss-of-function alleles. They make no active product - zero function

amorph

alleles that produce an active product with a new, different function

Neomorph

both alleles are simultaneously expressed in the heterozygote

codominance

one allele for a specific trait is not completely dominant over its paired allele. Ex: Red flower x White flower = Pink flower

incomplete dominance

people with a mutation that do not develop/show features of the mutation

incomplete penetrance

when one gene locus masks or modifies the phenotype of a second gene locus. Ex: black, chocolate, and yellow

epistasis

occurs when one gene influences two or more seemingly unrelated phenotypic traits

pleiotropy

the failure of homologous chromosomes or sister chromatids to separate properly during cell division

nondisjunction

Cytogenetics is the branch of genetics that studies the structure of DNA within the cell nucleus

cytogenetics

a picture of a person's chromosomes

karyotype

the number of complete sets of chromosomes in a cell

ploidy

the condition in which a normally diploid cell or organism acquires one or more additional sets of chromosomes.

polyploidy

Trisomy ('three bodies') means the affected person has 47 chromosomes instead of 46. Ex: down syndrome

trisomy (translocation)

Monosomy is when a diploid organism has only one copy of one of its chromosomes instead of two

monosomy (translocation)

is a mutation in which a part of a chromosome or a sequence of DNA is lost during DNA replication.

deletion (deficiency or Df)

new genetic material is generated during molecular evolution. It can be defined as any duplication of a region of DNA that contains a gene

duplication (Dp)

a chromosome rearrangement in which a segment of a chromosome is reversed end to end. An inversion occurs when a single chromosome undergoes breakage and rearrangement within itself. Inversions are of two types: paracentric and pericentric.

Paracentric inversions do not include the centromere and both breaks occur in one arm of the chromosome. Pericentric inversions include the centromere and there is a break point in each arm.

inversions (pericentric and paracentric)

the process of exchanging genetic material between chromosomes. A balanced translocation results in no gain or loss of material, while an unbalanced translocation may result in trisomy or monosomy of a particular chromosome

translocation

Dosage compensation is the process by which organisms equalize the expression of genes between members of different biological sexes.

dosage compensation

Having only a single copy of a gene instead of the customary two copies. All the genes on the single X chromosome in the male are 'hemizygous

hemizygous

refers to the sex of a species in which the sex chromosomes are not the same. For example, in humans, males, with an X and a Y sex chromosome, would be referred to as the heterogametic sex

heterogametic

A Barr Body is an inactivated, condensed X chromosome found in female cells. (named after discoverer Murray Barr)

barr body

contain sexual determination genes even though they are not sex chromosomes.

autosome

a measurable phenotype that depends on the cumulative actions of many genes and the environment. These traits can vary among individuals, over a range, to produce a continuous distribution of phenotypes. Examples include height, weight and blood pressure.

quantitative trait

protein function

what has a big impact on organism's phenotype?

replicated haploid (1)

secondary oocyte

replicated haploid (1)

first polar body

replicated diploid (2)

primary oocyte

Haploid (1)

sperm cell

diploid (2)

somatic cell

none

what stage of mitotic cell cycle has same number of chromosomes as a gamete

genes are on chromosomes

most important conclusion to come from the discovery of sex-linkage of the w gene in drosophila?