Bio Final

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DNA (acronym)

Deoxyribonucleic Acid

Double Helix

Shape of DNA

Adenine

Base Pair A, Paired with T in DNA or U in RNA

Guanine

Base Pair G, Paired with C

Cytosine

Base Pair C, Paired with G

Thymine

Base Pair T, Paired with A, Only in DNA

Deoxyribose

5 Carbon Sugar in DNA

Ribose

Sugar in RNA

Uracil

Base Pair U, Paired with A, Only in RNA

RNA (acronym)

Ribonucleic Acid

Chromosome

Fully condensed DNA in preparation for cell division

Chromatin

Uncondensed DNA, In a thread-like form

Chromatid

Sister Chromatids are in a duplicated chromosome, they are one side of the X

Histones

The proteins which DNA wraps around

DNA Replication

Process where DNA replicates

Topoisomerase

Untwists the Double helix

Primase

Catalyzes the synthesis of short-chain RNA because DNA can’t initiate the synthesis itself

Helicase

Breaks down hydrogen bonds between DNA strands

DNA polymerase

Joins the nucleotides of the new DNA

Ligase

Joins DNA fragments on the discontinuous strand

Anti-Parallel

Running in opposite directions (DNA strands do this)

Leading Strand

The Continuous strand in replication

Lagging Strand

Discontinuous strand in replication (broken apart and put back together by Ligase)

Okazaki Fragments

Fragments of the Lagging strand, put back together by Ligase

Mitosis

Diploid cell reproduction, only 1 cycle, last stage of the cell cycle

Centromere

Middle part of the X in a chromosome

Meiosis

Haploid cell reproduction, 2 cycles

Homologous Pair

Chromosome Pairs, Humans have 23 pairs

Cytokinesis

Division of Cytoplasm and Organelles for new cells

Cell Cycle

A series of events from one cell division to the next

G1

First part of the Cell cycle, cell grows and does its job

S

Synthesis, DNA replication in preparation for division

G2

Cell creates new proteins in preparation for division

Spindle Fiber

Strands used to pull chromosomes in anaphase and metaphase

Prophase (mitosis)

1st phase of mitosis, duplicated chromosomes are visible, nuclear membrane breaks apart

Metaphase (mitosis)

2nd phase of mitosis, Chromosomes align in the middle of the cell, spindle fibers attach

Anaphase (mitosis)

3rd phase of mitosis, sister chromatids separate and become independent chromosomes, spindle fibers drag them to opposite sides

Telophase (mitosis)

4th phase of mitosis, chromosomes uncondense, nuclear membrane re-appears, 2 daughter cells form

Cell Plate

Vesicles gather along the midline and form a cell plate

Contractile Ring

A ring formed outside of the cell membrane which pinches off the two cells

Cleavage Furrow

The area where the 2 animal cells are formed after telophase

Haploid

Half-DNA cells, sex cells, formed in meiosis

Diploid

Full DNA cells, autosomal cells, formed in mitosis

G0

Cell arrest, cell cycle stops, cells are in G1 permanently, includes heart cells and neurons

Synapsis

During Prophase 1 of Meiosis 1, homologous chromosomes line up closely together

Tetrad

2 aligned chromosomes, or 4 sister chromatids when crossing over

Crossing Over

During Prophase 1 of Meiosis 1, Sections of non-sister chromatids break off and switch places, creates genetic diversity

Random Alignment

During Metaphase 1 of Meiosis 1, Chromosomes randomly align themselves, creates more genetic diversity

Independent Assortment

Same thing as Random Alignment

Gametes

Haploid reproductive cells produced through meiosis

Egg

Haploid female sex cell

Polar Bodies

Leftover thingies after an egg cell is formed

Sperm

Haploid male sex cell

Parent cell

The cell daughter cells are made from

Daughter cells

the 2 new cells formed

Aneuploidy

The condition of having an abnormal number of chromosomes in a haploid set

Polyploidy

The condition of having and abnormal number of chromosomes in a diploid set

RNA polymerase

The enzyme which performs transcription. Unwinds DNA and attaches mRNA bases

Transcription

Copying of a gene’s recipe onto mRNA

Translation

3 steps, Initiation, Elongation, Termination. Creates polypeptides based on the information in the mRNA

mRNA

Messenger RNA, gets a message transcribes onto it and transports the message to the tRNA to be transcribed

rRNA

Ribosomal RNA, the main component of the Ribosomes, globular

tRNA

Transfer RNA, strange hairpin shape, reads the mRNA and makes the proteins

Amino Acid Chain

The new polypeptide formed after transcription

Ribosome

Organelle which makes the proteins and where protein synthesis occurs

Polysome

Poly ribosome, when multiple ribosomes cluster around the same mRNA

Point Mutation

A mutation where a single base is added, changed, or deleted. Has moderate to severe impacts

Base Change Substitution

When one base replaces another in a mutation

Insertion/Deletion

Bases are either added or removed in a mutation

Non-Frameshift Mutations

Insertion or deletion of a multiple 3 numbers of bases ex. losing AAG or gaining AAG,AAT. Usually moderate-severe impact

Frameshift Mutations

Insertion or deletion of a non-multiple of 3 number of bases ex. losing AU or gaining GCCT

Silent mutation

A base has changed but the correct amino acid is formed. There is no health impact

Missense Mutation

The base change causes the wrong amino acid to be formed, but the production of amino acids continues. Health impacts are moderate-severe

Nonsense Mutation

Where a single base changes similar to a missense mutation, however it codes for a premature stop. Health impacts are very severe

Allele

Alternative forms of the same gene

Autosome

All numbered chromosomes, all but X and Y, carry out the body’s regular functions

Sex Chromosomes

X and Y chromosomes

Polygenic inheritance

When more than one gene affects the outcome of the expressed characteristic. usually shown through a bell curve

Blood type inheritance

Type of polygenic inheritance. made up of the A, B and O alleles as well as the + and - parts

Codominance

2 alleles are equally expressed as traits, when a chicken is both black and white when having a black father and a white mother

Incomplete dominance

When one allele pair is not fully dominant over the other, resulting in a blend of the 2 traits. When a black father chicken and a white mother chicken have a grey chicken baby.

Microevolution

Short term changes in allele frequencies in populations

5 Fingers of Microevolution

1. Mutations, 2. Gene Flow, 3. Genetic Drift, 4. Sexual Selection, 5. Natural Selection

Gene Flow

The physical movement of alleles in and out of a population. Ex. Migration

Mutation (microevolution)

When a new allele is formed which is beneficial for the organism

Genetic Drift

Random change in allele frequency in a population over time due to chance alone

Bottleneck effect

When a huge percent of a population is randomly wiped out and the survivors are the only ones who pass on their genes, eliminating certain alleles and passing on others

Founder Effect

When a separated group starts a new colony with allele frequencies that are very different from the original population

Sexual Selection

When a trait makes it either easier or harder for the organism to reproduce, and making passing on genes either easier or harder

Natural Selection

The process where organisms with certain traits are best suited to survive and reproduce, thus passing on those traits to succeeding generations.

Adaptation

A favorable trait

Decent with modification

Modern animals are the modified descendants of older extinct species

Stabilizing Selection

The central form is favored and the extremes are less favored

Disruptive Selection

Extremes are more favored and central is selected against

Directional Selection

The trait shift in a clear direction towards one extreme

Allopatric Speciation

Due to geographical isolation: physical separation of members of a population

Sympatric Speciation

In the same geographical area, but separated due to other factors such as: habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation

Habitat Isolation

When species occupy different niches In the same are

Temporal Isolation

When species breed at different times, be it time of day or time of year

Behavioral Isolation

When species have different mating calls or rituals