BI 312 Exam 1

why study genetics?

understanding the spread and differences in virus/mutation

genetic testing for dugs

Which of these describes a genome?

the collection of genetic material in a cell or organisms

Suppose that life exists elsewhere in the universe. All life must contain some type of genetic information, but alien genomes might not consist of nucleic acids or have the same features as those found in the genomes of life on Earth

the ability to store the entire set of information an organism needs for reproduction and development

the ability to replicate the genetic information accurately for the next generation

What is the most inclusive definition of a model organism (model system)?

an organism with a biological system that is representative of the same system in other organisms

define a gene

a chromosomal region that codes for a functional transcript

a functional unit of heredity

define an allele

an alternative form of a gene

define a chromosome

long DNA molecule visible during mitosis

large genetic element that carries genes essential to cellular function

How does the structure of DNA encode genetic information?

the sequences of bases

what is transmission genetics?

principles of heredity

determines how traits are passes from one generation to the next

what is molecular genetics?

the chemical nature of the gene itself; how genetic information is encoded, replicated, and expressed

what is population genetics?

explores the genetic composition of populations and how that composition changes over time

Prokaryotes consist of two fundamentally different types of bacteria: eubacteria and _____.

archaea

Which process occurs during the telophase stage of the cell cycle?

the chromosomes arrive at the spindle poles

What is the major function of shugoshin during interphase of the cell cycle?

Shugoshin is involved in anaphase I, where it protects cohesin at the centromere

which of these are diploid cells?

spermatogonium

Assume that a drug is developed that prevents the prometaphase stage of mitosis from occurring, but does not prevent any stages of mitosis prior to prometaphase from occurring, nor does it interfere with any part of interphase. What will be the immediate consequence of this drug?

spindle microtubules will not be able to attach to chromatids

A protein called _____ protects cohesin at the centromere and prevents the separation of chromatids during anaphase I of meiosis.

shugoshin

what is not a characteristic of viruses?

viruses have an evolutionary relationship

To what part of a chromosome do the kinetochore proteins attach?

centromere

When do the sources of genetic variation in meiosis occur?

meiosis I

Elphaba swabs the inside of her mouth. She then rubs the buccal swab on a microscope slide, adds a drop of methylene blue, and observes it under a light microscope. She sees a number of blue masses, each mass with a darker blue spot. Therefore, Elphaba is considered a (n) _____ organism

eukaryotic

The protein _____ holds sister chromatids together during mitosis and meiosis

cohesion

Liam needs a microscope with high enough magnification to observe the bacteria cells he has cultured from sauerkraut. Which of these microscopes has *just enough* magnification to allow viewing of bacteria?

a scanning electron microscope (SEM) can achieve resolution greater than 1 nanometer

what is pangensis?

early concept of heredity proposing that particles carry genetic information from different parts of the body to reproductive organs

what is preformationism?

early concept of inheritance proposing that a mini adult (homunculus) resides in the egg/sperm and grows during development

\-all traits come from one parent

what is blending inheritance?

proposed the trait were of offspring was a blend of both parents

what is germ-plasm theory?

a theory stating that cells in the reproductive organs carry a complete set of genetic information

where are genes located?

on the chromosome

homologues

__pairing__ at __meiosis__ and having the same structural features and pattern of genes.

Define prokaryotic cells

relatively small, typically less than 10 micrometers in size

lack membrane organelles

define eukaryotic cells

a complete copy of DNA stored in multiple chromosomes

\-both prokaryotic and eukaryotic cells contain DNA and use ribosomes

A cell has a circular chromosome and histone proteins associated with its DNA, but lacks a nuclear membrane.

The cell belongs to Archaea because it has histones proteins, which are present in Archaea and Eukaryota but absent in eubacteria

what are the functions of mitotic cell division?

replacement of cells

asexual reproduction

growth of multicellular organisms

what happens at the G1/S checkpoint?

maintains cell until necessary enzymes for replication are synthesized

what happens at the G2/M checkpoint?

detection of the DNA damage after replication

what happens at the spindle-assembly checkpoint?

ensures that each chromosomes is attached to spindle fibers from opposite poles

What happens during anaphase I of meiosis?

homologous chromosomes separate, but sister chromatids remain joined at their centromeres

kinetochore

a multi-protein complex; where microtubules attach

telomeres

repeated sequence at the end of chromosomes; protective; important in aging and cancer

define interphase

the nuclear membrane is present and chromosomes are relaxed

define prophase

chromosomes condense

each chromosome possess two chromatids

the mitotic spindle forms

define prometaphase

the nuclear membrane distinguishes

spindle microtubules attach to chromatids

define metaphase

chromosomes line up on the metaphase plate

define anaphase

sister chromatids separate and move towards opposite poles

define teolphase

chromosomes arrive at spindle poles

the nuclear membrane reforms and the chromosomes relax

where does meiosis take place?

in meiocytes

define fertilization

the fusion of haploid gametes

what are the main events of meiosis?

1. replication of DNA
2. adhesion of sister chromatids
3. paring of homologous
4. segregation of homologous


1. segregation of sister chromatids

define meiosis I

separation of homologous chromosome pairs, and reduction of the chromosome number half

define meiosis II

separation of sister chromatids; also know an equational divison

define prophase I

synapsis: close paring of homologous chromosome

tetrad: closely associated four-sister chromatids of two homologous chromosomes

crossing over: crossing over of chromosomes segments from the sister chromatid of one chromosome to the sister chromatid of the other synapsed chromosoem

define metaphase I

random alignment of homologous chromosome pairs along the metaphase plate

define anaphase I

separation of the homologous chromosomes and the random distribution of chromosomes into two newly divided cells

plants

sporophyte produces haploid cells (spores) via meiosis

gametophyte produces haploid cells via mitosis

double fertilization

triploid (3n) endosperm feeds the embryo

what holds sister chromatids together?

cohesion

what enzyme separates sister chromatids?

separase

what is chromatin made of?

DNA and histone proteins

where do the spindle microtubules attach?

at the centromere

(later they attach at the kinetochore)

what are the four places the centromere can be located?

submetacentric (closer to top)

metacentric (middle)

telocentric (closer to bottom)

acrocentric (at the tippy top)

what are the stages interphase is divided in?

G1, S, G2

G1

the cells growdivision and proteins necessary for cell divison are synthesized

S

DNA synthesis, chromosomes are replicated

G2

biochemical reactions happen to make the cell ready to divide

where does crossing over take place?

Prophase I

what is synapsis?

a very close paring association

what is crossing over?

homologous chromosomes exchange genetic information

shuffles alleles on the same chromosome

where do two chromosomes cross?

chiasma

define interkinesis

period between meiosis I and meiosis II where the nuclear membrane reformed, spindle fibers break down, and chromosomes relax

what is recombination?

the creation of new combinations of alleles on a chromatid

the basis for this is crossing over

define random distribution

shuffles alleles on different chromosomes

what is the production of male gametes called?

spermatogenesis

where does spermatogenesis occur?

the testes

what are spermatogonia?

diploid cells

primary spermatocyte

still diploid

secondary spermatocytes?

haploid from the completion of meiosis I

spermatids

produced after meiosis II

haploid

polar body

contains half the cytoplasm and full amount of chromosomes

probably won’t divide

(after meiosis I)

what is the ovum?

the mature female gamete

what is a sporophyte

multicellular diploid

produce haploid spores through meiosis

part of the flower

what is a gametophyte

multicellular haploid

produces haploid gametes through mitosis

what dies the stamen contain?

diploid reproductive cells called microsporocytes

what do microsporocytes do?

undergo meiosis to produce four haploid microspores

what does the ovary undergo?

the ovary contains diploid cells called megasporocytes which undergo meiosis to produce four haploid megaspores

\-only one megaspore survives

Of the following ideas postulated by Gregor Mendel, which one requires at least two genes to be demonstrated?

genes assort independently in humans

How is a true breeding yellow‑seeded pea plant different from a hybrid yellow‑seeded pea plant?

they have the same phenotype but different genotypes

monohybrid crosess

crosses between parent that differ in a single characteristics

backcross

a cross between an F1 genotype and one of its parents genotypes

testcross

an individual of unknown genotype is crossed with a homozygous recessive genotype for the trait in question

principle of independent assortment

alleles at different loci separate independently of one another

principle of segregation

two alleles at a locus separate when gametes are formed

Which term describes an individual who carries two different alleles at a locus that results in a recessive phenotype?

compound heterozygote

____ genes suppress the effect of other genes at a different locus.

Epistatic

What blood genotype is considered the universal receiver?

AB