Biology Unit 2: Genetics
What does heredity mean?
The passing of traits from parents to their offspring
What is genetics?
The study of heredity and variation
Within a cell, where is genetic information contained?
DNA
What does DNA stand for?
Deoxyribonucleic acid
What is a gene?
The portion of the DNA molecule that codes for a particular trait
What is the specific location of a gene on a DNA molecule called?
Locus
What are some examples of different organisms with their pairs chromosomes?
Human-23, Chicken-39, Kangaroo-6
What is the production of offspring from a single parent?
Asexual reproduction
Through what reproduction is an offspring genetically identical to its parent?
Asexual Reproduction
What are three examples of asexual reproduction?
Budding, cloning, and fragmentation
What is sexual reproduction?
The production of offspring from two sex cells
What is chromatin?
Tangled fibrous complex of DNA and protein in a eukaryotic nucleus
What is the name given to genetic material during interphase?
Chromatin
What is a single chromosome joined by?
The centromere
What are the two structures of a chromosome called?
Sister chromatids
True/False: Sister chromatids contain identical genetic information.
True
What are the three reasons for mitosis?
Permit growth, repair damaged cells, and replace dead cells
What stage if mitosis is 90% of the cycle?
Interphase
In interphase, what part is called G1?
Rapid cell growth
In interphase, what part is called S?
Duplication of chromosomes
In interphase, what part is called G2?
Preparation of cell division
What are the stages of mitosis in order?
Interphase, prophase, metaphase, anaphase, telophase, and cytokinesis
In what phase if mitosis do chromosomes shorten and thicken?
Prophase
In what phase of mitosis do animal cell centrioles move to opposite poles of the cell?
Prophase
What attaches to the centrioles during prophase?
Spindle fibres
What anchors chromosomes to the spindle fibres during prophase?
Centromere
In what phase do chromosomes move toward the cell equator?
Metaphase
What happens in anaphase?
Centromeres split and sister chromatids move to opposite poles of the cell
In what phase do chromosomes reach opposite sides of the cell?
Telophase
In what phase do spindle fibres dissolve?
Telophase
In telophase, what begins to reform at each end of the cell?
Nulcear membrane
What is the division of cells at the end of mitosis?
Cytokinesis
What happens to animal cells in cytokinesis?
Membrane develops a furrow making two separate cells
What happens to plant cells in cytokinesis?
Cell plate forms, eventually resulting in a new cell wall
True/False: Number and information contained in the chromosomes in each daughter cell is different than the parent cell.
False. The number and information contained is identical
What is cloning?
The process of forming identical offspring from a single cell or tissue
What are engineered organisms called?
GMOs (Genetically modified organisms)
How does cloning animals work?
Take nucleus out of an unfertilized egg, put it into a different animals enucleated egg, once an embryo is formed, place it in the iterus if another animal
What are the possible uses of cloning?
To get organs, cloning endangered species
What are gametes?
Sex cells (sperm and egg cells)
What is the name for when the a sperm cell meets an egg cell?
Fertilization
What is a zygote?
The first cells formed when a sperm cell and egg cell meet
What is the term referring to one set of chromosomes within a cell (represented with n)?
Haploid
What is the term referring to two sets of chromosomes within a cell (represented with 2n)?
Diploid
What are pairs of chromosomes called?
Homologous chromosomes
What is the process involving two stages of cell division and resulting in four haploid cells?
Meiosis
What are the two stages of meiosis?
Meiosis I and meiosis II
What happens in prophase I?
Replicated homologous chromosomes perform synapsis
What is synapsis?
The process of chromosomes pairing
What is a tetrad?
The resulting structure if synapsis
What is crossing over?
The process of chromosomes becoming intertwined and exchanging genetic information
What happens in metaphase I?
Homologous structures move to cell equator
What happens in anaphase I?
Homologous structures move to opposite poles along spindle fibres
What happens in telophase I?
Nuclear membrane forms around homologous structures at each pole and cytokinesis occurs
What happens in prophase II?
New spindle fibres form from each pole and nuclear membrane dissolves
What happens in metaphase II?
Chromosomes line up at cell equator
What happens in anaphase II?
Sister chromatids separate and migrate to opposite poles
What happens in telophase II?
Nuclear membrane reforms and cytokinesis occurs
What is the term for chromosomes from each parent randomly placed on either sude of the homologous chromosomes?
Random assortment
What is gametogenesis?
The formation of sex cells in animals
What is spermatogenesis?
The spermatocycle that proceeds through meiosis resulting in four sperm cells
What is oogenesis?
The oocyte that proceeds through meiosis resulting in one ootid (egg) and three polar bodies
How many oocytes do baby females have?
2,000,000
When are primary oocytes suspended until?
Puberty
How many oocytes are released in reproductive years?
300-500
What gender has XX chromosomes?
Female
What gender has XY chromosomes?
Male
What are the sex chromosomes in a cell?
The 23rd pair of chromosomes in a karyotype
What are autosomes?
The 22 chromosomes in a cell that are not sex cells
What is a karyotype?
A picture of chromosomes that are arranged in homogous pairs
What is nondisjunction?
When homologous chromosomes fail to separate during meiosis I
How many chromosomes do gametes have?
22 and 24
What is monosomy?
One copy of a chromosome (23+22)
What is trisomy?
Three of one chromosome (23+24)
What is an example of monosomy?
Turner syndrome
What is an example of trisomy?
Down syndrome
What is klinefelter syndrome?
A person with sex chromosomes XXY
What type of cells does mitosis occur in?
Somatic cells
What type of cells does meiosis occur in?
Sex cells
In what cycle are daughter cells diploid?
Mitosis
In what cycle are the daughter cells haploid?
Meiosis
True/False: The number of chromosomes in the new daughter cells compared to the original cell in mitosis is the same.
True
True/False: The number of chromosomes in the daughter cells compared to the original cell in meiosis is the same.
False. The number of chromosomes in the daughter cells compared to the original cell after meiosis is half the amount
What cycle produces two cells in the end?
Mitosis
What cylce makes four cells in the end?
Meiosis
Is an egg cell haploid or diploid?
Haploid
Is a hair cell haploid or diploid?
Diploid
What is the result of a cross between two different lines or species?
A hybrid
What is an allele?
Alternate forms of a gene
What is a characteristic?
A phenotype that can be inherited (height)
What is a trait?
Variation within a characteristic (tall/short)
What is the alleles of an organism represented by letters?
Genotype
What is a phenotype?
The observable traits of an organism
What is a genotype with like alleles?
Homozygous
What is a genotype with different alleles?
Heterozygous
What is a cross involving only one trait?
Monohybrid
What is a chart used to show possible results of a cross?
Punnett square
Who discovered genetics?
Gregor Mendel
Who discovered DNA?
Friedrich Miescher
What are the 3 parts of a DNA molecule?
Deoxyribose sugar (5-carbon ring), phosphate group, and nitrogenous base
What to the theee parts of a DNA molecule combined called?
A nucleotide
What are the 4 types of nitrogenous bases?
Adenine, guanine, thymine, and cytosine
What nitrogenous bases go together?
A and T, C and G
What is a double helix?
Twisted staicase DNA structure
What makes the backbone of a strand of DNA?
The binding of deoxyribose sugar and phosphate
Nitrogenous base of one strand forms hydrogen bonds with a complementary base. What does a complementary strand look like?
The opposite letter from the typical pairs (A becomes T, C becomes G)
What is a mutation?
A change in the genetic code
What is point mutation?
A nitrogenous base is substituted, added, or deleted
What types of point mutation cause frame shifting?
Insertion (added nitrogenous base) and deletion (deleted nitrogenous base)
What are chromosomal mutations?
Errors to a significant portion of the chromosome
What is a coded region of a DNA called?
An exon
What is a non coding region of DNA called?
An intron
True/False: A mutation that occurs in a coding region can be inherited.
True. However, a mutation that is not located in a coding region will not be inherited