Biology Final Exam

Covalent Bonds

Strongly bonds the bases, sugars, and phosphate groups

Hydrogen bonds

\-Occur between the two strands and involve a base from one strand with a base from the second in complementary pairing

\-Weak on it’s own but strong together

Gene

Segments of DNA that contain instructions for building the molecules that make the body work

Nucleotide

Molecule consisting of a nitrogen base, a phosphate group, and a sugar

Nucleic Acid

\-Macromolecule made up of nucleotides

\-DNA & RNA

Chromosomes

\-Made up of proteins and DNA organized into genes

\-Separate pieces of DNA in a cell

\-Found in the nucleus of cells

Chromatin

\-DNA and proteins that make up a chromosome

\-Less organized than chromosomes

Purines

\-Larger than pyrimidine

\-Two-ring structure

\-Adenine & Guanine

Pyrimidine

\-Smaller than purines

\-One-ring structure

\-Thymine, Uracil, & Cytosine

Adenine

\-Nucleotide, pairs with thymine in DNA

\-Pairs with uracil in RNA

Guanine

Nucleotide, pairs with cytosine

Thymine

Nucleotide, pairs with adenine in DNA

Cytosine

Nucleotide, pairs with guanine

Chargaff’s Rule

\-DNA from any cell of all organisms should have a 1:1 ratio (Base Pair Rule) of pyrimidine and purine bases

\-Amount of guanine is equal to cytosine

\-Amount of adenine is equal to thymine

Helicase

Enzyme that unwinds DNA

DNA Polymerase

\-Enzyme that builds a new DNA strand by adding complementary bases

\-Builds from 5’ to 3’

Ligase

Binds Okazaki Fragments

(Okazaki fragments are short, discontinuous strands of DNA on the lagging strand)

Point Mutation

A mutation in the DNA that changes a single nucleotide

Silent Mutation

A mutation that occurs in the DNA but doesn’t change anything

Frameshift Mutation

An insertion/deletion of a nucleotide base that shifts the entire sequence occurring after the mutation

Interphase - G1

Cell growth

Interphase - S

Chromatids duplicate to create 2 sister chromatids or one replicated chromosome connected by one centromere

Interphase - G2

Cell growth

Prophase

Centriole duplicates and moves to the other side of the cell. Chromosomes are still in the nuclear envelope

Prometaphase

\-Also known as late stage prophase

\-Nuclear envelope dissolves and microtubules attach, beginning to bring the chromosomes into a straight line

Metaphase

Chromosomes fully align in the center of the cell

Anaphase

Sister chromatids pulled to opposite poles of the cell

Telophase

Mitotic spindles dissolve and cell division begins. Nuclear envelopes reform (there are two now)

Cytokinesis

Cell pinches, dividing the cytoplasm. Forms a cleavage furrow and divide the cell

Fission

Cell stretches and makes two identical copies--very quick. No genetic variation in the population

* Bacteria, protists, unicellular fungi

Fragmentation

Can grow back pieces or new organisms from the original

* Starfish, some worms, fungi, plants, lichens

Budding

New organism grows by mitosis and cell division on the body of the parent--bud gets big enough, breaks off

* Yeast, hydra

Vegetative Reproduction

Portion of plant falls off/cut off, placed in a positive environment to grow into an identical version of the original

* Plants

Parthenogenesis/Agamogenesis

Egg can develop an embryo without being fertilized. Reproduction that doesn’t involve male gamete

* Many plants and some animals

Haploid

Having a single set of unpaired chromosomes

Diploid

Containing two complete sets of chromosomes, one from each parent

Testes

Where sperm is made

Ovaries

Where ova/egg are held before being released

Gamete

Cell made for sexual reproduction with 23 chromosomes

Sperm

Male gamete

Egg/Ova

Female gamete

Zygote

Fertilized egg/ova

Fertilization

Sperm and egg combine

Homologous Chromosomes

Chromosomes that match in size, shape, and general placement of genes (loci of genes are the same)

Crossing Over

Homologous chromosomes exchange genes

Independent Assortment

Each pair of chromosomes independently aligns at the cell equator. There is a 50% probability of the maternal or paternal chromosome facing a given pole

Nondisjunction

An abnormal number of chromosomes in gametes due to mistakes during meiosis

Sex Chromosomes

AKA X and Y chromosomes XX = Female XY = Male

Autosomes

\-One of the numbered chromosomes

\-Numbered in relation to their sizes (Big --> Small)

Peptide Bonds

A covalent bond formed between two amino acids

Polypeptides

A polymer of amino acids joined together by peptide bonds

Uracil

Nucleotide, pairs with adenine in RNA

Transcription

The process of making an RNA copy of a gene's DNA sequence

Translation

The process by which a cell makes proteins using the genetic information carried in mRNA

mRNA

\-Messenger RNA

\-Contains instructions that your body can read to create a special type of protein

rRNA

\-Ribosomal RNA

\-Serves as a location for protein synthesis

\-Forms ribosomes

tRNA

\-Transfer RNA

\-Has its corresponding amino acid attached to its end

\-When a tRNA recognizes and binds to its corresponding codon in the ribosome, the tRNA transfers the appropriate amino acid to the end of the growing amino acid chain

Ribosome

Synthesizes proteins according to instructions written in mRNA

Codon

A sequence of three consecutive nucleotides in a DNA or RNA molecule that codes for a specific amino acid

Template

RNA

Anticodon

\-Three-nucleotide sequence found on tRNA that binds to the corresponding mRNA sequence

\-Opposite from a codon

Amino Acid

Building blocks for proteins

RNA Polymerase

\-Synthesizes RNA by following a strand of DNA

\-Responsible for copying a DNA sequence into an RNA sequence during the process of transcription

Genome

\-Haploid set of chromosomes in a gamete or microorganism, or in each cell of a multicellular organism.

\-Complete set of genes or genetic material present in a cell or organism.

Allele

Different forms of a gene

Transcription Factor

Proteins that bind to DNA sequences and regulate the transcription of genetic information from DNA to messenger RNA

Genotype

An organism’s genetic material

Phenotype

An organism’s physical characteristics

Homozygous

\-Having two identical alleles

\-AA, aa

Heterozygous

\-Having two different alleles

\-Aa

Dominant

\-Traits that will always show up if present

\-Expressed with a capital letter

Recessive

\-Traits that will only show up if no dominant alleles are present

\-Expressed with a lowercase letter

Locus

The location of a specific gene on a chromosome

Probability

A measurement tool that predicts the chances of an offspring being inherited with a particular trait

Common Ancestor

An ancestor shared between two or more organisms

Homologous Structures

\-Similar physical features in organisms

\-Share a common ancestor

\-Serve different functions

Vestigial Structures

Structures that served a purpose for past ancestors but are currently useless

Fossils

The remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock

Embryological Similarities

\-Similarities in embryos are evidence of common ancestry

\-When traits of one type of animal appear in the embryo of another type of animal

Extinct

Species that are no longer in existence

Allopatric Speciation

When a species gets separated by a geographic barrier, which results in the species evolving into 2 different species

Immigration

When an animal establishes a home in a habitat because it has resources it can utilize or because the habitat is ideal for them

Gene Flow

The transfer of alleles or genes from one population to another

Genetic Drift

A change in allele frequencies caused by random events

Biological Species Concept

A group of populations that potentially can interbreed and produce fertile offspring

Morphological Species Concept

Classification of a species by structural features

Ecological Species Concept

Views a species in terms of its ecological niche (what they eat, where they live, etc.)

Phylogenetic Species Concept

Identifies based on morphology, DNA sequences, or biochemical pathways

Natural Selection

A process in which organisms better suited to their environment are able to survive and reproduce more offspring

Variation

\-The difference in DNA sequences between individuals within a population

\-More variation --> Better chances of the species surviving as a whole

Fitness

\-An organism's ability to pass its genetic material to its offspring

\-Higher reproduction --> Higher fitness

Adaption

\-Process by which a species becomes fitted to its environment

\-Result of natural selection's acting upon heritable variation over several generations

Acquired Traits

Traits you develop in your lifetime (can be both behavior and physical) and cannot be passed on

Inherited Traits

Traits coded in our DNA; can be passed onto the next generation

Artificial Selection/Selective Breeding

Breeding done by humans to select traits that are desirable for humans

Taxonomy and Classification

\-Always written in two parts, the genus name written first, and the species name second.

\-The scientific name is italicized. If it is handwritten, it is written cursive/underlined.

\-The first letter of the genus name is a capital letter (the species name is lowercase)

Levels of Taxonomy

\-Kingdom

\-Phylum

\-Class

\-Order

\-Family

\-Genus

\-Species