Chapters #1-3 Flashcards
- is a key to Biology. Biology is the study of living things.
- The scientific study of Heredity
- Geneticists study how traits and diseases are passed from one generation to the next
- Understanding what genes are, how they are passed from one generation to the next, and how they work is essential to understanding life.
Genetics
- The fundamental unit of heredity, made of DNA
- compromised of sequences of nucleotides contained on a double-stranded helical DNA molecule.
Gene
- DNA is comprised of a polymer (linked string) of chemical subunits (basic unit of DNA structure)
- made up of a base with phosphate and sugar.
nucleotides
four different type of nucleotides
-Combinations of these four nucleotides define which amino acids will be used to make specific proteins in the cell. Human’s have 20 different amino acids
- Adenine (A) & Thymine (T)
- Guanine (G) & Cytosine (C)
- Any observable property of an organism
- -Actions of gene products (proteins) produce visible traits such as eye color and hair color.
Trait
How many chromosomes do humans have
46 chromosomes which makes us a diploid formed from two haploids
Augustinian monk whose work on pea plants in the mid-1800’s provided the foundations for the science of genetics.
Gregor Mendel
where genes are contained, are found in the nucleus of human cells and other higher organisms, and is separated during formation of egg and sperm
chromosomes
-Study inheritance patterns and how traits are passed from generation to generation
Transmission Genetics
-Construction of family trees used to follow transmission of genetic traits in families (inheritance). The only way we can study humans is by construction a family tree.
Pedigree Analysis
the principle, originated by Gregor Mendel, stating that during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent. Also called Mendel’s first law
Law of Segregation
- Study of the organization and arrangement of genes on a chromosome
- Study of chromosome number and structure
- area of genetics where chromosome structure and abnormalities are studied
Cytogenetics
- A complete set of chromosomes from a cell that has been photographed during cell division and arranged by size in a standard order
- The purpose of making this is to determine what the individual is
Karyotype
XX
XY
XX=Female
XY=Male
who determines the gender of the child
the father
how many chromosomes do Down syndrome have
47
- Techniques whereby DNA fragments are linked to self-replicating vectors, which are replicated in a host cell, often bacteria
- Genetically modified organisms
- Carry and express genes from another species
Recombinant DNA Technology
- Genetically identical molecules, cells, or organisms, all derived from a single source or parent
- Gene therapy
- Normal genes are transplanted into humans with defective copies to treat genetic diseases
Clone
-the misuse of genetics has affected social policy
-the attempt to improve the human species by selective breeding
-Early to mid-1900’s: US attempted to improve the population by preventing immigration and the introduction of less desirable traits
-Laws restricting reproductive rights and requiring certain individuals to be sterilized were instituted
-Used by Nazis in Germany to promote mass killings of individuals believed to be genetically inferior and ultimately genocide
-In the early part of the twentieth century, this exhibited at fairs and similar events were used to educate the public about the proposed
benefits of these policies.
Eugenics
the field of biology that studies the structure and function of genes at a molecular level and thus employs methods of both molecular biology and genetics
Molecular Genetics
experimental technique that uses genes to treat or prevent disease.
Gene Therapy
the haploid set of chromosomes in a gamete or microorganism, or in each cell of a multicellular organism
Genome
the branch of molecular biology concerned with the structure, function, evolution, and mapping of genomes.
Genomics
study of genetic variation within populations, and involves the examination and modelling of changes in the frequencies of genes and alleles in populations over space and time
population genetics
the mistaken idea that human traits are determined solely by genetic inheritance, ignoring the contribution of the environment
hereditarianism
single nucleotide differences between and among individuals in a population or species
single nucleotide polymorphism
a set of genetic markers located close together on a single chromosome or chromosome region
haplotype
analysis of genetic variation across an entire genome searching for associations (linkages) between variations in DNA sequence and a genome region encoding a specific phenotype
genome-wide association study
The use of recombinant DNA technology to produce commercial goods and services
Biotechnology
A single nucleotide polymorphism alters DNA by only one ___
Nucleotide
basic research has a goal of understanding how something works. If Dr. Ralph uses a discovery resulting from basic research to produce a commercial product, he is performing what kind of research?
Applied research
If you believe the traits are determined only by what genes you have, you do not think that ___ has anything to do with the person you are.
environment
an event which occurs in prophase 1 of meiosis, but not prophase II is
synapsis of homologous chromosomes
An event that occurs in anaphase 1 of meiosis, but not anaphase II is
the separation of homologous chromosomes
Chromosomes are not usually visible in non-dividing cells because
they are highly uncoiled
Near the end of prophase, each chromosome can be seen to be composed of two
chromatids
The cell cycle stage called G1 is not important in normal development; if it did not occur, the cells resulting from mitosis would
become smaller with each successive division
Meiosis occurs in a diploid cell results in the formation of
four
each of the cells formed in meiosis contain the ___ number of chromosomes
haploid
By comparison, mitosis occurring in a diploid cell results int reformation of ___ cells each of which contain the ___ number of chromosomes
two; diploid
Lysososmes are cellular organelles that contain
digestive enzymes
With respect to the genetic information they carry, bone cells, nerve cells, and skin cells are all ___
identical
The statement in the previous question can be made because cells of different types are formed from the fertilized egg by the process of
Mitosis
controls the exchange of materials between the inside of the cell and the cell’s environment
plasma membrane
Of all the cells involved in the production of gametes, a ___ has the same chromosome content as a skin cell.
spermatogonia or oogonia
include small sugars and large polymers of sugars
Carbohydrates
consist of fats and oils, phospholipids and steroids
Lipids
are polymers of amino acids and carry out a multitude of functions and activities
Proteins
are polymers of nucleotides. They store and transfer genetic information in the cell
Nucleic acids
- A structure composed of two or more atoms held together by chemical bonds
- The Plasma membrane encloses the cytoplasm which is a complex mixture of molecules and organelles
Molecule
-Cytoplasmic membrane-enclosed structures that have specialized function
Organelle
- System of cytoplasmic membranes arranged into sheets and channels
- Synthesizes and transports gene products
Endoplasmic Reticulum (ER)
-Cytoplasmic particles that aid in the production of proteins
Ribosomes
- Membraneous organelles composed of a series of flattened sacs
- Sort, modify and package proteins synthesized by the ER
Golgi Complex
-Membrane bound organelles in eukaryotic cells that contain digestive enzymes
Lysosomes
- Membrane-bound organelles in the cytoplasm of all eukaryotic cells
- Sites of energy production
mitochondria
- Threadlike structures in the nucleus that carry genetic information
- 46 chromosomes (diploid number, 2n) are present in most human cells
chromosomes
The membrane bound organelle in eukaryotic cells that contains the chromosomes
Nucleus
A nuclear region that functions the synthesis of ribosomes
nucleolus
The DNA and protein components of Chromosomes
chromatin
In humans, the X and Y chromosomes that are involved in sex determination
Sex chromosomes
Chromosomes other than sex chromosomes
Autosomes
The sequence of events that takes place between successive mitotic divisions
Cell cycle
The period of time in the cell cycle between mitotic division
interphase
-form of cell division that produces two cells, each having the same complement of chromosomes as the parental cell.
Mitosis
-The cytoplasmic division phase of cell division
Cytokinesis
- one strand of a duplicated chromosome
- Joined by a centromere to its sister chromatid
chromatid
- Region of chromosomes to which microtubule fibers attach during cell division
- Centromere location gives a chromosome its characteristic shape
Centromere
- two chromatids joined by a common centromere
- Each carries identical genetic information
Sister Chromatid
-Stage in mitosis when chromosomes become visible and contain sister chromatids joined at the centromere
Prophase
-Stage in mitosis when chromosomes move and become arranged at the middle of the cell
metaphase
-Stage in mitosis in which the centromeres split and daughter chromosomes begin to separate.
anaphase
- Last stage of mitosis
- chromosomes of the daughter cells decondense
- Nucleus reforms
telophase
what we need to know about mitosis:
- Mitosis and cell division is an essential process
- Human cells are genetically programmed to divide about 50 times (known as Hayflick limit)
- This limit allows growth to adulthood, and repairs such as wound healing
- Alterations in the limits to cell division can lead to genetic disorders (such as premature aging) or to cancer.
- The Physical Exchange of Parts between chromosome pair in meiosis.
- The process will produces new combinations of genes in offspring. For this reason it is impossible for any two children to be genetically identical (aside from identical twins).
crossing over
A form of cell division that produces four haploid cells containing only one copy (paternal or maternal) of each chromosome
meiosis
-Each chromosome is represented twice as a member of a homologous pair
diploid (2n)
-Each chromosome is represented once, in an unpaired condition
haploid (1n)
- Maternal and paternal, with identical gene loci
- Chromosomes that physically pair during meiosis
Homologous Chromosomes
- Gametes receive random combinations of maternal and paternal chromosomes
- Result of meiosis I
Assortment
Sex cells (eggs and sperm)
gametes
of maternal and paternal chromosomes in metaphase I. Chromosome pairs line up at random
Random Assortment
How are humans formed?
by meiosis and crossing over
One of the possible alternative forms of a gene. Usually distinguished from the rallies by its phenotypic effects
allele
Mitotically active cells in the gonads of males that give rise to primary spermatocytes
Spermatogonia
The four haploid cells produced by meiotic division of a primary spermatocycte
spermatids
Mitotically active cells that produce primary oocytes
oogonia
The large cell produced by the first meiotic division
Secondary oocyte
cells produced in the first and second meiotic division in female meiosis that contain little cytoplasm and will not function as gametes
Polar bodies
The haploid cell produced by meiosis that becomes the functional gamete
Ovum
- Pollen (male plant version of sperm)
- Pollination (Bees, wind, and water help transfer pollen)
- To Pollinate (when the pollen enters the stigmas of the female plant)
- Offspring (F1-First generation)
crossing
Male and female plants
cross pollinated plants
Male is on top and female is on bottom
self pollinated plant
- Father of Chemistry
- Discovered genetics and heredity
Gregor mendel
-Why do we begin examining inheritance by discussing Gregor Mendel and pea plants?
because he is the father of genetics
-Trait expressed in the F1 (heterozygous) condition
dominant trait
-Trait repressed in the F1 but re-expressed in some members of the F2 generation.
recessive trait
-Observable properties of an organism (physical characteristics)
phenotype
-The specific genetic constitution of an organism
genotype
-Fundamental units of heredity
genes
-Members of a gene pair separate from each other during gamete formation.
segregation
-test determined to find phenotypes
test cross
having identitcal alleles for one or more genes
homozygous
carrying two different alleles for one or more genes
heterozygous
The random distribution of alleles into gametes during meiosis
independent assortment
The position occupied by a gene on a chromosome
locus
use of a family history to determine how a trait is inherited and to estimate risk factors for family members
pedigree construction
a diagram listing the members and ancestral relationships in a family; used in the study of human heredity
pedigree
first affected family member who seeks medical attention for a genetic disorder
proband
expression of a phenotype that is intermediate to those of the parents
incomplete dominance
full phenotypic expression of both members of a gene pair in the heterozygous condition
codominance
small sample sizes in experiments can introduce errors into the analysis of the results. to avoid these errors, Mendel used ___
large sample sizes
One member in each pair of genes and one member in each pair of chromosomes is inherited from an individuals
parents
A gene has multiple alleles. This means that ___
there are multiple possible phenotypes for that gene
at a locus that has multiple alleles, the genotype of an individual can have a maximum of ___
2 alleles
if a gene has three different alleles, there are ___ different genotypes possible
6
genetic counseling may be desirable when
an individual risks passing on a disease to his or her offspring
