BIO Exam 1

Transcription is carried out by a protein complex called

RNA polymerase

Translation is carried out by _______ and the ___________ , which is made of RNA and proteins

tRNAs, Ribosome

Transcription

the DNA sequence of a gene is used as a template to create an RNA molecule

Translation

the sequence of RNA bases is read and used to create a protein with a specific amino acid sequence

Gene expression

The flow of genetic information from genes to RNA to proteins

Some genes code for

protein

Genes ALWAYS encode for

RNA

Mutations arise due to:

-DNA replication mistakes

- Mutagens

- Errors Recombination in Meiosis

Mutagen

environmental agents that cause DNA damage

Small Mutations

Change, add, or remove DNA sequence for a few bases

Chromosomal Mutations

Large DNA sequences(1000's of bases long) are copied, deleted, or rearranged within and between chromosomes

Cells in eukaryotes are ________, meaning that they have two copies of each chromosome

diploid

Homozygous

have two identical alleles of a gene

Heterozygous

have two different alleles of a gene

Genotype

The set of genetic alleles an organism posses

Phenotype

The physical trait encoded by the genetics

What holds two strands of DNA together?

Hydrogen bonds between nitrogenous bases

Adenine binds to Thymine with

2 H Bonds

Guanine binds to cytosine with

3 H Bonds

purine

adenine and guanine

pyrimidine

thymine and cytosine

In DNA, information is always read

3' to 5'

New DNA and RNA molecules are synthesized

5' to 3'

genome

all the hereditary information (DNA base pairs) that an organism posses

Prokaryotes store their genomes in a

singular circular chromosome

Eukaryotes store their genomes in

multiple linear chromosomes

genetic locus

a specific location on a chromosome

chromosome

large double stranded DNA molecules with a unique DNA sequence

chromatid

a single chromosomes condensed for mitosis

Sister Chromatids

two copies of the same chromosome

Mitotic Chromosomes

Two sister-chromatids with condensed DNA joined at a centromere

M phase: Cell Division

- Mitosis

- Cytokinesis

Interphase: Cell growth and function

-Gap 1

- Synthesis

- Gap 2

S Phase (what occurs during this phase)

DNA replication

Chromosomes are loosely organized during

Interphase

Sister Chromatids form during

S Phase

DNA complement _________ during S-phase and is ________ during mitosis

doubles, halved

Ploidy

the number of SETS of chromosomes (or copies of the genome) that a cell contains

Karyotypes

a method to visualize chromosomes number and ploidy

Meiosis

A series of two cell divisions that create haploid gamete cells with a unique complement of genes

Meiotic cells are__________ when they enter Meiosis

tetraploid

Meiotic cells become _________ after Meiosis I

diploid

Meiotic cells become ________ after Meiosis II

haploid

Three Main Processes During Meiosis:

Random Assortment of Homologous Chromosomes

Crossing Over/Recombination

Random Mutations

During random assortment, maternal and paternal chromosomes are divided up at random between __________ during ______________

daughter cells, meiosis

Homologous chromosomes swap ____ in a process called "Crossing over" or "Recombination"

DNA

Recombination creates new combinations of _________ on a chromosome

alleles

Mistakes during DNA replication prior to meiosis can create

new mutations

Mistakes during recombination can cause

chromosomal mutations

Mistakes in chromosome movements can cause

aneuploidy

non-disjunction

The failure of chromatids to separate during Anaphase

Aneuploidy

Having too many or too few copies of a chromosome relative to the cell's ploidy

Monosomy

having only one copy of a specific chromosome

Trisomy

having three copies of a specific chromosome

community of organisms and the physical environment in which the organisms live

ecosystem

Plants drive ________________ by converting CO2 to glucose in photosynthesis

carbon fixation

Glucose produced by plants moves through food webs and is released by

cellular respiration and decomposition

Organic carbon is trapped in __________ and in __________ created by geological processes (fossil fuels)

biomass, carbon sinks

Nitrogen fixation

conversion to organic forms of Nitrogen like NH3 and NO3-

(carried out by microbes)

Excess nitrogen is excreted by many organisms as

urea and ammonia

Denitrification

Microbes convert organic nitrogen back to inorganic N2 gas in a process called

Phosphate is released back to the environment by

excretion and decomposition

Plants take up ________ from soil/water, allowing it to enter food webs

phosphate

limiting nutrients

those that are least abundant in an ecosystem and, therefore, limit its productivity

autotrophs

produce organic compounds from inorganic substrates

heterotrophs

must acquire organic compounds from other organisms

Energy flows from ___________ to ____________

autotrophs to heterotrophs

cellular respiration

a series of chemical reactions that harness the energy produced by break down glucose and uses it to produce ATP.

Autotrophs, produce their own energy

(Which trophic level?)

Primary producers (highest energy)

directly consume producers

Primary consumers

consume herbivores

secondary consumers

consume other carnivores

Tertiary Consumers

Detritovores

consume waste and decomposing material

Most energy is lost as ______ and __________.

A smaller fraction is retained in __________

heat and waste, biomass

biomass

the total mass of all organisms in the trophic level

productivity

measure of the energy in a trophic group that is determined by the rate at which organisms generate new organic matter

Gross Primary Productivity

the total amount of energy generated by primary producers

Net Primary Productivity

the energy that is produced after taking into account loss of energy to respiration and waste

Species richness

the number of species present in a community

Species evenness

the number of individuals per species in addition to the total number of species

keystone species

those whose effects on the composition of communities are greater than one might expect based on their abundance

niche

The total of all the ways an organism uses the resources of its environment. It encompasses the physical habitat and ecological role of a species

fundamental niche

hypothetic niche that encompasses the entire environment that a species is capable of using

realized niche

the actual environment in which the species can establish a stable population

Interspecific competition

occurs when two different species attempt to use a resource that is present in limited amounts

competitive exclusion

occurs when one species uses a resource more efficiently than another and eventually eliminate the other from its local environment

Resource partitioning

occurs when species adapt to utilize different parts of a niche to avoid direct competition

Predation

occurs when one organism consumes another

Interference competition

occurs when species physically interact to obtain a resources

Coevolution

occurs when two species undergo reciprocal evolutionary changes and leads to Symbiosis

Parasitism

a type of inter-species interaction in which one species benefits at the expense of the other

Herbivory

a type of inter-species interaction involving the consumption of plants and plant parts

Mutualism

a type of inter-species interaction in which both species involved benefit

Commensalism

a type of inter-species interaction in which one species benefits and the other is unharmed

Facilitation

a type of indirect interaction where one species creates a suitable habitat for another

Ecology

the study of the relationships of organisms to one another and the environment

Populations are defined by three key features:

size, range, and density

density independent factors

-natural disasters

-unexpected changes in temperature

density dependent factors

-competition

-diseases and parasites

Corridors

facilitate the movement of individuals between patches which helps persist populations