Cell Bio Terms Final Exam Flashcards
What does sexual reproduction do that doesn’t happen in asexual reproduction ?
Introduces a variation in the combinations of traits among offspring
What does asexual reproduction produce
Genetically identical copies of a parent
What are genes
Regions in an organisms DNA that encode information about heritable traits
What are alleles?
Different forms of the same gene
What is meiosis
A cytoplasmic division (sexual reproduction)
What does meiosis result in
4 haploid cells
What is a zygote
First cell of a new individual
What happens in meiosis 1
Homologous chromosomes separate
What happens in meiosis 2
Sister chromatid separate
What is the key stage of meiosis 1 and what happens in it
Prophase 1. Synapsis (homologous chromosomes) to form tetrads and pairing at chiasmata. Crossing over.
What is the name of the process of sperm creation
Spermatogenesis
What is the name of the process of egg creation (females)
Oogenesis
What is the result of Spermatogenesis
4 haploid spermatids are formed
What is the result of oogenesis
1 haploid ovum and 3 haploid polar bodies
Describe how sperm are formed
Diploid male sex cell ➡️ (meiosis 1 and cytoplasmic division) primary spermatocyte [diploid] ➡️ (meiosis 2) secondary spermatocytes [haploid] ➡️(cytoplasmic division) spermatids [haploid] ➡️ 4 sperm
Describe how ovum are formed
Oogonium (female sex cell) [diploid] ➡️ (meiosis and cytoplasmic division) primary oocyte [diploid] ➡️ (meiosis 2) first polar body [haploid] and secondary oocyte [haploid] ➡️ three polar bodies [haploid] and one ovum [haploid]
What is fertilization
The fusion of two haploid gametes to result in a diploid zygote
Where does mitosis occur
Somatic cells
Where does meiosis occur
Germ line cells
Meiosis takes a cell that’s ________ and makes it _________
Diploid, haploid
What is a spermatozoan
A mature sperm.
Describe a spermatozoan
Head with DNA and enzyme cap. Mid piece with mitochondria. Flagellum for movement.
Who did the pea plant experiment
Gregor Mendel
Describe why the garden pea was a good model for genetics studies
True breeding
Both self and cross fertilization possible
Short generation time
Easy to work with
What is a mutation
A permanent change in a gene
What is a true breeding lineage
Offspring inherit identical alleles for a trait
What is a hybrid
Has non identical alleles for a trait
What does heterozygous mean
Non indentical alleles of a gene
What does homozygous mean
Identical alleles of a gene
What does a dominant allele do ?
Masks the effect of a recessive allele paired with it
Capital letters signify what
Homozygous dominant
Lower case letters signify what
Homozygous recessive
What is a gene called if it is Aa
Heterozygous
What is gene expression
The process by which information in a gene is converted to a structural or functional part of a cell or body
What is a genotype
Particular alleles an individual carries ie. Ww
What’s a phenotype?
An individual’s observable traits
Ie. widows peak
What does P stand for
Parents
What does F stand for
Filial (offspring)
What does F1 stand for
First generation offspring of parents
What does F2 stand for
Second generation offspring of parents
What are monohybrid experiments
Crosses that check for a dominance relationship between two alleles at a single locus
What is a locus
A location
Give an example of a cross between homozygous individuals
AA x aa
Give an example of a cross between heterozygous individuals
Aa x Aa
What is probability
A measure of the chance that a particular outcome will occur
What is a Punnett square
A grid used to calculate the probability of genotypes and phenotypes in offspring
What is Mendels law of segregation
Two genes of each pair seperate during meiosis and end up in different gametes
What is a test cross
A method of determining if an individual is heterozygous or homozygous dominate
How do you perform a test cross
Individual of an unknown genotype is crossed with one that is homozygous recessive
Ie. AA x aa or Aa x aa
How many traits do dihybrid experiments involve
2
What is a dihybrid experiments
Tests for dominance relationships between alleles at two loci
What is Mendels law of independent assortment
Many genes are sorted into gametes independently of other genes
What is an incomplete dominance
Intermediate phenotype (what you see ) ie. red + white = pink
What is codominance
Two non identical alleles of a gene are both fully expressed in heterozygotes so neither is dominant or recessive
Ie. abo blood group system
What is pleiotropy
One gene product influences two or more traits
What is continuos variation
Traits with a range of small differences
What is a bell curve
When continuos phenotypes are divided into measurable categories and plotted as a bar chart, they form a bell shaped curve
What sex chromosomes do males have
XY
What sex chromosomes do females have
XX
What are autosomes
Chromosomes that are the same in makes and females
What is a karyotype
Micrograph of all metaphase chromosomes in a cell arranged in pairs by size, shape and length
What stops dividing cells at metaphase
Colchicine
Can a dominant autosomal allele be expressed in homozygotes and heterozygotes
Yes
What is progeria
Genetic disorder that results in accelerated aging
What are some x linked recessive disorders
Hemophilia, red-green color blindness and duchenne muscular dystrophy
What are the 4 types of chromosomes structural changes
Duplication
Inversion
Translocation
Deletion
What is aneuploidy
Too many or too few copies of one chromosome
What is polyploidy
Three or more copies of each chromosome
What is nondisjunction
When a pair of chromosomes fails to seperate properly during mitosis or meiosis
What is monosomy
N-1 gamete
What is trisomy
N + 1 gamete
What is trisomy 21
Down syndrome
What is a pedigree
A standardized chart of genetic connections
What are the three types of inheritance
Autosomal recessive
Autosomal dominant
X- linked recessive inheritance
In autosomal recessive does the trait skip a generation
Typically
What is autosomal dominant
Trait appears in every generation. Allele is expressed even in heterozygotes
In an x linked recessive who is the carrier
Females
In x linked recessive can a son inherit recessive alleles from his father
No but a daughter can
What is genetic counseling
Information collected is used to predict the probability of having a child with a genetic disorder
What is genetic screening
Widespread routine testing for alleles associated with genetic disorders
