Chapter 2 Flashcards
Variant
The particular form of a trait
Ex. Brown eyes, blue eyes
Cross
Matings
In genetics, a mating between chosen parents
F0 Generation
The initial generation
The original founding population
F1 Generation
The offspring of the F0 generation
Note this will continue to F2, F3, etc .
F2 Generation
The offspring of the f1 generation
Genes
Two particle. One inherited from the mother and one from the father.
A segment of the chromosomes that produces a recognizable effect on phenotype and segregates as a unit during gamete formation
Gametes
In animals
An egg or sperm
Gametes
In animals
An egg or sperm
Independent assortment
Principle discovered by Mendel
That each of the genes at a single locus on a pair of homologous chromosomes is equally likely to be transmitted when gametes (eggs and sperms) are formed
Happens during Meiosis
The probability that a particular chromosome will enter a gamete is 0.50 and is independent of whether other non homologous chromosomes enter the same gamete.
Thus knowing that an individual received a particular chromosome from its mother (and thus a particular allele) tells nothing about the probability that it received other, non homologous chromosomes from its mother.
Chromosome
A linear body in the cell nucleus’s that carries genes and appears during cell divison
Contained in every cell and replicated during cell division - a special kind of cell division that creates gametes.
Staining cells with dyes reveals different chromosomes are marked with different banding patterns
Chromosome
A linear body in the cell nucleus’s that carries genes and appears during cell divison
Contained in every cell and replicated during cell division - a special kind of cell division that creates gametes.
Staining cells with dyes reveals different chromosomes are marked with different banding patterns
Nucleus
The distinct part of the cell that contains the chromosomes
Eurokryotes (fungi, protozoans, plants, and animals) all have nucleated cells: prokaryotes (bacteria) do not
Nucleus
The distinct part of the cell that contains the chromosomes
When a cell divides, the nuclei divides too
Eurokryotes (fungi, protozoans, plants, and animals) all have nucleated cells: prokaryotes (bacteria) do not
Eukaryotes
fungi, protozoans, plants, and animals
all have nucleated cells
prokaryotes
Bacteria
Do not have nucleus
prokaryotes
Bacteria
Do not have nucleus
Mitosis
The process of cell division of somatic cells (normal cells.) through which new diploid cells are created
Somatic cells
Normal body cells
Diploid
Of a cell
Containing pairs of homologous chromosomes of each pair is inherited from each parent
Also refers to organisms who’s somatic (body) cells are diploid
All primates and humans are diploid
Diploid
Of a cell
Containing pairs of homologous chromosomes of each pair is inherited from each parent
Also refers to organisms who’s somatic (body) cells are diploid
All primates and humans are diploid
Homologous chromosomes
Pairs Inside chromosomes
Pairs who’s members have similar shapes and staining patterns
Sets of chromosomes that have the same genetic loci but often contain different alleles.
Human cells contain 23 pairs of chromosomes - one of each pair comes from the mother and the other from the father
Meiosis
Sex cell creation
The process of cell division in which haploid gametes (eggs and sperm) are created.
Each gamete contains only one copy of each chromosome (compared to mitosis where they contains a homologous pair of chromosomes) = haploid
Haploid
Of a cell
Containing only one copy of each chromosomes
Gametes are haploid , so are the cells of some asexual organisms
Zygote
The cell formed by the union of an egg and a sperm
When one haploid sperm and one haploid egg to produce a diploid zygote
It is a single cell that then divides mitotically over and over to produce the millions of cells that make up an individuals body.
Alleles
One or two or more alternative forms of genes
Varieties of a single genes
Individuals with Two copies of the same allele are homozygous.
Individuals with the same alleles are heterozygous
Homozygous
Individuals that have a chromosome that carry two copies of the same allele at a single genetic locus
Diploid organism
Organisms who’s somatic are homozygous are also called homozygotes
AA or aa
Heterozygous
Of a diploid organism
Organisms that carry copies of two different alleles for a particular genetic locus
Organisms are called heterozygotes
( Aa )
Genotype
Refers to a particular combination of genes or alleles that an individual carries.
The combination of alleles that characterizes an individual at some set of genetics loci
Ex.populations with only the A and S alleles at the hemoglobin Locust, that locus has only three possible genotypes : AA, AS/SA, SS
Genotype is the AA , Aa, or aa of an organism and phenotype is the Yellow or Green peas
Phenotype
Refers to the observable character of the organism
Indidivudals with the same phenotype may have different genotypes
Ex. Colour of the peas in Mendez’s experiment
Genotype is the AA , Aa, or aa of an organism and phenotype is the Yellow or Green peas
Dominant
Of an allele
Used to describe the A allele because individuals with only one cope of the A allele have the same phenotype
Results in the same phenotype whether in the homozygous or the heterozygous state
Recessive
Use to describe the a allele
Expressed in the phenotype only when it is in the homozygous state (aa)
Has no affect on phenotype in heterozygous ( Aa )
Punnet Square
A diagram that uses genes (or alleles) frequencies to calculate the genotype frequencies for the next generation
Recombination
The creation on grew genotypes as a result of the random segregation of chromosomes and of crossing over
The process is very important for maintaining variation in natural population
Demonstrates that sexual reproduction shuffle genes that affect shuffle genes that affect different traits , thereby producing new combinations of traits
Ex. Crossing plants with smooth yellow send and plants with green wrinkled seeds. All the F1 generation were smooth and yellow, F2 generation were 9 smooth yellow, 3 smooth green, 3 wrinkled yellow, 1 wrinkled green
Locus
The position that a particular gene occupies on a chromosome
A gene for a particular trait occur at a particular site on a particular chromosome.
They are arranged on the chromosome in a line. (Like beads on a string)
Genome
All the genetic information carried by an organism
All the genes carried on the chromosomes
Linked
Of genes
Being located on the same chromosome
The closer together the two loci are the more likely they are to be linked
When loci for different traits occur close to each other on the same chromosome
Unlinked
Of genes
Located on different chromosomes
When loci are on different chromosomes
Crossing over
The exchange of genetic material between homologous chromosome s during meiosis
Causes recombination of genes carried on the same chromosome
Chromosomes frequently tangle and break as they are replicated during meiosis. Chromosomes are not always preserved intact and genes on one chromosome are sometimes shifted from one member of a homologous pair to another.
If two loci are located close together on a chromosome, crossing over will be rare and the rate of recombination will be low.
If two loci are located far apart then crossing over will be common and the rate of recombination will approach the rate for genes in different chromosomes.
Deoxyribonucleic acid
Aka DNA
The molecule that carries hereditary info in almost all living organisms
DNA consists of two very long sugar phosphate backbones called strands to which the bases adenine, cytosine, guanine, and thymine are bound. Hydrogen binds between the bases bind the two strands.
Chromosomes contain two structurally complex molecules: protein and deoxyribonucleic acid
Basis
One of four molecules - adenine, guanine, cytosine, and thymine that are bound to the DNA backbone.
The DNA Backbone is alternating sequences of sugar and phosphate molecules - one of these four molecules attach to each sugar.
Different sequences of basis encode the info necessary for protein synthesis
DNA backbone
The DNA Backbone is alternating sequences of sugar and phosphate molecules - one of these four molecules attach to each sugar.
Adenine
One of the blur basis on the DNA molecule
The complementary base of adenine is thymine.
Guanine
One of the fourbases on the DNA molecule
Complementary base of guanine is cytosine
Cytosine
One of the four bases of the dna molecule
Complementary base of cytosine is guanine
Thymine
One of the four bases of the dna molecule
Complementary base is adenine
Which of the four bases of the dna molecule bind with each other
Thymine only bonds with Adenine
Guanine only bonds with cytosine
Protein coding genes
A gene that encodes instruction for making proteins
One of the three most important ways that DNA affects phenotypes
Enzymes
A protein that serves as a catalyst increasing the rate at hwich a larticular chemical reactions occur at a given temperature
Enzymes can control the chemical composition of cells by causing some chemical reactions to occur much faster than others.
Regulator gene
A dna sequence that regulates the expression of a structural gene often by binding to an activator or repressor
Determines conditions under which the message in encoded in a protein coding gene will be expressed.
Play a crutial role in shaping the differentiation of cells during development
One of the three most important ways that DNA affects phenotypes
Biochemical pathway
Any of the chains of chemical reactions by which organisms regulate their structure and chemistry
Complex
Real organisms take in many compounds and each compound is involved in a complicated tangle of branches called pathways.
Ex. One set of enzymes cause glucose through a pathway that yield energy, and a different set of enzymes cause the glucose to go down a pathway that store energy.
Proteins
Large mkecutes consisting of a long chain of amino acids
Many proteins are enzyme catalysts : others perform structural functions
Amino acids
A molecule that is linked in a chain to form a protein
20 different amino acid molecules - all which share the same molecular backbone but have a different side chain
Primary Structure
The sequence of amino acids that make up a protein
Sequence of amino acid side chains.
It’s what makes one protein different from others.
Ex. Think of a protein as a long railroad train, where there are. 20 different kinds of cars, each representing a different amino acid - the primary structure is a list of the type of cars in the order that they occur .
Tertiary structure
The 3D folded shape on a protein
Crucial to the catalytic function
The way a protein folds depends on the sequence of amino acid molecules that make up its primary sequence so the function of an enzyme depends on the sequence of the amino acids that make up an enzyme depends
Hemoglobin
A protein in blood that carries oxygen including two a (alpha) and two B (beta) subunits.
Transport oxygens from the lungs to the tissues via bed blood cells.
The proteins folds into a roughly spheric glob and the oxygen is bound to the protein near the Center of the globe.
Sickly cell anemia
A severe form of anemia tha5 afflicts people who are homozygous for the sickle cell gene
Codons
A sequence of three dna basis on a dna molecule that consists of one “word” in the message used to create a specific protein
Each “word” specifies a particular amino acid
There are 64 codons ( meaning 64 possible 3 letter combinations ) - 4 possibility’s for the first letter, 4 for the second letter, 4 for the third letter. (Note this is between DNA encodes messages using a 4 letter alphabet)
Ribonucleic acid
RNA
A long molecule that plays several informant roles in protein synthesis
Differs from DNA in that is has a slightly different chemical backbone and it contains the base uracil instead of thymine
Uracil
One of the four basis on the RNA molecule
Replaces thymine in DNA .
Complementary to adenine
Messenger RNA (mRNA)
A from of rna that carries specifications for protein synthesis from DNA to the ribosome
Aid in protein synthesis
Transfer RNA (tRNA)
A form of RNA that facilitates protein synthesis by first binding to amino acids in the cytoplasm and then binding to the appropriate site on the messenger RNA
There is at least one distinct form of tRNA for each amino acids
Amino acid molecules are bound to tRNA
Anticodon
The sequence of bases on a transfer RNA molecule that binds complementary to a particular mRNA codon.
Ex. MRNA codon AUC corresponds to the anticodon UAG because A binds to U, U binds to A, and C binds to G.
Ribosome
A small organelle composed of protein and nucleic acid that temporarily holds together the mRNA and the tRNA during protein synthesis
mRNA fist binds to the ribosome at a binding site then moves the binding site on codon at a time. Each codon on mRNA enters the binding site, a tRNA with a complimentary anticodon is drawn from the complex soup of chemicals inside the cell and bound to the mRNA. the amino acids bound to the other end of the tRNA is then detached from the tRNA and added to one end of the growing protein chain. The process repeats for each mRNA until the end of the mRNA Molecule passes through the ribosome and a new protein is ready for action.
How does a new protein created with mRNA and tRNA in protein synthesis?
mRNA fist binds to the ribosome at a binding site then moves the binding site on codon at a time.
Each codon on mRNA enters the binding site, a tRNA with a complimentary anticodon is drawn from the complex soup of chemicals inside the cell and bound to the mRNA.
the amino acids bound to the other end of the tRNA is then detached from the tRNA and added to one end of the growing protein chain.
The process repeats for each mRNA until the end of the mRNA Molecule passes through the ribosome and a new protein is ready for action.
Organelles
A portion of a cell that is enclosed in a membrane and has a specific function
Ex. Mitochondria and the nucleus
Prokaryotes
An organism that lack cell nuclei or chromosomes
Ex. Bacteria
Eukaryotes
An organism whose cells have a cell nucleus and chromosomes
Ex. Plants, birds, humans / Animals
Introns
A segment of dna in eukaryotes that is not translated into protein
Non coding sequences
Exon
A segment of the DNA in eukaryotes that is translated into proteins
Repressor
A protein that decreases transcription of a regulated gene
Ex. When there is no lactose in the environment a repressor protein binds to one of the two regulatory sequences and interferes with RNA polymerase , an enzyme necessary for transcription , thereby preventing the protein coding genes from beings transcribed
Activator
A protein that increases transcript of a regulated gene
Combinatorial control
The control of gene expression in which more than one regulatory protein is used and expression is allowed only in specific combination of conditions
The existence of multiple regulatory sequences allows for this
More complex in eukaryotes
Spliceosomes
An organelle that splice the mRNA in eukaryotes after the introns have been snipped out
Noncoding RNA (ncRNA)
Molecules of RNA that do not code for proteins, including transfer RNA, ribosomal RNA, and microRNAs
MicroRNA (miRNA)
Short segments of RNA that are involved in the translation of mRNA into protein and gene expression
Some are involved in regulating development and cell differentiation in complex organisms
A form of ncRNA
Long coding RNAS (lncRNA)
RNA molecules linger that 200 neucleotides
IncRNA has many functions including gene regulation
Have a wide variety of functions
Important in regulating the expression of genes during development
