Bio 131 - Lecture Exam

Chapter 5-7

What cells undergo mitosis?

All body cells

How many cells do you get after mitosis?

2 diploid / daughter cell and 46 chromosomes

What is difference between animal and plant cells during mitosis?

Cytokenesis

•The parent animal cell is pinched into two, forming a cleavage furrow and leaving two independent offspring cells.

•The parent plant cell forms a cell plate and leaves two independent offspring cells

Animal cell in cytogenesis

The parent animal cell is pinched into two, forming a cleavage furrow and leaving two independent offspring cells.

Plant cell in cytokinesis:

The parent plant cell forms a cell plate and leaves two independent offspring cells

Cell cycle phases

1.Interphase (G1àSàG2)

2.Mitotic phase (Mitosis àCytokinesis)

How does mitosis differ from meiosis?

Meiosis has two rounds of genetic separation and cellular division while mitosis only has one of each.

What cells undergo meiosis?

Sex cells / gametes

How many cells do you have at the end? How many chromosomes does each cell have at the end of meiosis? 

4 haploid / daughter cell — 23 chromosome

What is genotype?

is its underlying genetic makeup, the alleles it is carrying.

What is phenotype?

•is its observable traits.

What does the term "heterogeneous" mean?

Heterogeneous refers to a mixture or composition of different elements or substances that are not uniform throughout.

What does the term "homogenous" mean?

Homogenous refers to a substance or mixture that has a uniform composition throughout, with no visible differences or variations.

When do we use monohybrid crosses and dihybrid crosses?

Monohybrid crosses are used to study the inheritance of a single trait, while dihybrid crosses are used to study the inheritance of two different traits simultaneously.

Where do you see a difference between Mitosis and meiosis?

meiosis involves the exchange of genetic material between homologous chromosomes, leading to genetic variation, whereas mitosis does not.

What is homozygous?

Having two identical alleles for a given gene.

What is heterozygous?

Having two different alleles for a given gene.

What are linked genes?

Genes located close enough together on a chromosome that they are usually inherited together.

What are alleles?

An alternative version of a gene.

What is incomplete dominance?

A type of inheritance in which the phenotype of a heterozygote (Aa) is intermediate between the phenotypes of the two types of homozygotes (AA and aa).

What is codominance?

Codominance is a genetic phenomenon where both alleles of a gene are fully expressed in the phenotype of an organism. This means that neither allele is dominant or recessive, and both contribute to the observable traits.

What chromosome are sex-linked diseases found on?

X chromosome

What is non-disjunction?

is when chromosomes fail to separate properly.

What is the main difference between DNA and RNA?

DNA (deoxyribonucleic acid) is a double-stranded molecule that carries genetic information, while RNA (ribonucleic acid) is a single-stranded molecule involved in protein synthesis.

Where is DNA made in a cell?

nucleus of a cell.

What enzyme is required to make DNA?

DNA polymerase.

Where is RNA made in a cell?

nucleus of a cell.

What enzyme is required to make RNA?

RNA polymerase

Where are proteins made in a cell?

the ribosomes of a cell.

What organelles and components are required to make protein?

ribosomes, endoplasmic reticulum (ER), and amino acids.

What is replication?

creates identical DNA strands

What is the process of DNA replication?

the process by which a cell makes an identical copy of its DNA. It occurs during the S phase of the cell cycle. The double-stranded DNA unwinds and separates into two strands.

What is transcription?

is the transfer of information from DNA to a molecule of messenger RNA (mRNA)

what is the process of transcription?

begins when RNA polymerase binds to a specific region of DNA. After a molecule of RNA is synthesized, it is altered in several ways before it departs the nucleus.

what is translation?

Is a process through which a molecule of messenger RNA (mRNA) is used to produce a molecule of protein

what is the process of translation?

–Initiation

–Elongation

–Termination

1. What are different types of RNA 

messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA)

Leading strand

5’ to 3’

same direction as the movement of the replication fork.

which one is made continuously?

Leading Strand

which one is made in fragments?

Lagging Strand

Lagging strand

What are these fragments called?

"Okazaki fragments

What helps to connect these fragments together to ensure the result is one complete DNA strand?

DNA polymerase, RNA primers, and DNA ligase

what is silent mutation

does not change the amino acid produced (because some amino acids are encoded by more than one RNA seqeuence so the protein is unchanged

Nonsense mutation:

changes an amino acid codon to stop a codon. This will produce a shortened protein that is always defective

Frameshift mutation:

a mutation occurring when nucleotides are inserted in or deleted from a gene and the number inserted or deleted is not a multiple of three, resulting in the improper grouping of subsequent nucleotides into codons

Describe natural selection

a process in which organisms with certain inherited characters are more likely to survive and reproduce than are organisms with other characters; unequal reproductive success

What is affected by natural selection, individuals or populations?  

populations

• What does fitness mean in regards to biological organisms?

the ability to survive to reproductive age, find a mate, and produce offspring.

• What is a fossil

form when organisms die, fall into accumulating sediment, and are compressed into rock.

how does fossil support the idea of evolution 

by documenting the existence of ancient organisms and the changes in life forms over geological time

• Do individuals or populations evolve? 

populations

what is a gene pool

•consists of all versions of all the genes carried by all the individuals in a population.

what permits genetic variations to occur. 

•Genetic variation in a gene pool can arise through mutation.

what does sexual reproduction ensure

that genes are randomly mixed.

• What is Microevolution?

•A generation-to-generation change in the gene pool, which is evolution occurring on its smallest scale.

What is mutualism?

An interspecific interaction in which both partners benefit.

What is symbiosis?

Pertaining to symbiosis, the close physical association of members of different species.

• What factors contribute to gene pool evolution?

Mutation, gene flow, sexual reproduction, genetic drift, natural selection, bottleneck and founder effect, and sexual selection. Altering gene number or position.

• What reproductive barriers prevent different species from breeding with one another? 

• Behavioral isolation

• Mating time differences

• Habitat isolation

what is Behavioral isolation

Members of a species often identify each other through specific rituals.

what is Mating time differences:

Many species are able to reproduce only at specific times.

what is Habitat isolation:

If species live in slightly different habitats, they may never meet.

Why is competition in ecosystems important to understand? How does this affect species?

–More offspring are born than can be supported by limited resources; not all individuals survive and reproduce.

2 important points species of Darwin made:

•First, modern species have descended from common ancestors (evolution).

•Second, natural selection is the mechanism of evolution.

what did Darwin observe?

Darwin observed that populations produce more individuals than the amount that can survive

what did Darwin conclude?

Darwin concluded that competition was a factor for all living things

what was Darwin’s conclusion

favorable variations will be naturally selected and natural selection can lead to evolution

what are important points about evolution

•Individuals don’t evolve.

•Natural selection works with heritable traits.

•Evolution does not have a goal.

what is adaptation

is the accumulation of these favorable traits in a population over time.

Individual with traits that enhance survival and reproduction will have, on average, more offspring.

TRUE.

what is evolution

is defined only in terms of changes in a population over time.

what is population

is a group of individuals of the same species living in the same place at the same time.

•Traits that enhance survival and reproduction will be represented with increasing frequency in the gene pool.

TRUE.

species

•is a population that is capable of interbreeding to produce healthy, fertile offspring.

Reproductive barriers maintain species

Mechanical incompatibility

Gametic incompatibility

Hybrid weakness

what is Mechanical incompatibility

Members of different species often cannot mate because their anatomies are incompatible.

what is Gametic incompatibility

The gametes (sperm and egg) of different species usually cannot fertilize each other.

what is Hybrid weakness

Offspring of two species may be unfit, or they may be sterile.

Prokaryotes

Bacteria and Archaea

Eukaryotes (called Eukarya).

–Plantae, Fungi, and Animalia.

domain

The broadest category of classification; the domains bacteria and archaea are prokaryotes while eukaryotic contains organisms with eukaryotic cell

kingdom

Within the domain eukaryotic, there are three kingdoms that are generally agreed upon:

• plantae, fungi, Animalia

phylum

Different phyla of animals are distinguished by certain fundamental characteristics of their body forms

• chordates

class

The phylum of chordates includes classes such as reptiles, amphibians, mammals, and several classes of fish

• mammals

order

Within the class of mammals, the order of carnivores is recognized by dental anatomy

• carnivories

family

The order of carnivores contains at least a dozen families including the canines and the felines

• felines

genus

A genus contains one or more closely related species. The four members of the genus panther are the only cats that can roar

• big cats

species

The most narrow category of classification; species are recognized by the ability of its members to interbreed with each other

• tiger

•Observation: Overproduction

–More individuals are born than can be supported by the environment.

•Observation: Limited resources

–The amount of resources (such as food, water, shelter, sunlight) stays relatively constant.

•Conclusion: Competition

–More offspring are born than can be supported by limited resources; not all individuals survive and reproduce.

•Observation: Variation

–Darwin also observed that no two individuals are alike.

•Conclusion: Natural selection

–Those individuals with variations that make them best suited to their environment will, on average, be more likely to survive and reproduce.

•Observation: Heritability

–The traits of an organism are likely to be passed to the next generation.

•Conclusion: Evolution

–Because traits are passed from one generation to the next, and because certain members are more likely to survive and reproduce, a population will change over time, becoming better suited to its environment.

when were antibiotics first discovered

1940s

how can fossils be dated

using their geological position or through radiometric dating: measures half-life of radioactive elements in organic matter

what is gene therapy

•is the alteration of a person’s genes in order to treat or cure a disease by inserting the “correct” D N A into the cell.

how does gene theory begin

with isolation of the normal gene from a healthy person.

1.Enzymes are used to produce an R N A version of the target D N A gene.

3.The R N A gene is combined with an infectious, but harmless, retrovirus.

3.The virus is used to infect a patient’s bone marrow cells, transferring the proper gene to a diseased individual.