Meiosis + Sexual Reproduction Flashcards
Heredity
The transmission of traits from one generation to the next
–> Also known as “inheritance”
Impacts of inherited variation:
Permits flexibility and survival of a population in a changing environment
Genetics
The study of heredity and inherited variation
–> Attempting to answer: “What accounts for similarities + variation?”
Transmission (of traits)
The passage of DNA, on chromosome, from parents to offspring
–> What makes inheritance possible
Genes
DNA segments that encodes for specific traits that emerge as we develop
Genes are the _________ _________ to our parents and account for family ____________
1) Genetic link
2) Resemblance
Most genes program cells to synthesize…
specific enzymes and proteins whose cumulative action produces an organism’s inherited traits
Gametes
Reproductive (sex) cells that transmit genes from one generation to the next
Somatic Cells
All cells of the body EXCEPT gametes (and their precursors)
Ploidy
The # of SETS of chromosomes within a given cell
Haploid
= n
–> Single set of chromosomes
Diploid
= 2n
–> Two sets of chromosomes
Human haploids and diploids
Gametes = haploid = 23 chromosomes
Somatic Cells = diploid = 46 chromosomes
We inherit one chromosome of each pair from…
Each parent = one maternal chromosome set + one paternal chromosome set
Even after DNA is replicated to form duplicated chromosomes, we still refer to the cells as being…
Haploid or diploid
–> BECAUSE the cell still only has one or two sets of info REGARDLESS of how many chromatid copies there are of that info
Homologous Chromosomes
The maternal and paternal copies of a chromosome found in diploid cells
Similarities Between Homologous Chromosomes
1) Length
2) Centromere Position
3) Type of genes/Order of genes found/gene loci
Differences Between Homologous Chromosomes
Can possibly differ in alleles
–> Same genes, different alleles
Homologous chromosomes carry genes that…. (1)
BUT the _______________________(2) of these genes may differ between them
1) Control the same inherited characteristics
2) Variants/versions of these genes
Homologous chromosomes ARE NOT…
Sister Chromatids (which are IDENTICAL copies of each other)
Locus
Location/Position of a gene in a chromosome
Allele
A variant or form of a gene
How many alleles of each genes do diploids have?
2 alleles of each gene
(One from mother, one from father)
Sex Chromosomes
Chromosome that determine sex (X + Y)
Sex Chromosomes ARE NOT…
Homologs
Our 46 chromosomes =
44 (22 pairs) autosomes + 2 sex chromosomes
Autosomes
All chromosomes EXCEPT sex chromosomes
–> Essentially, the homologous chromosomes
Karyotype
An ordered display of all human chromosomes arranged in pairs –> How we can study chromosomes
How does karyotype work?
Homologs stain similarly making it easy to pair up homologs by shared size/length and staining
2 different types of cell division:
1) Asexual Reproduction
2) Sexual Reproduction
Asexual Cell Division
A single individual (cell) is the sole parent
–> = Genetically identical offspring (clones)
1) Mitosis
2) Binary Fission
Sexual Cell Division
TWO parents contribute DNA to one offspring
–> = Genetically different (unique) offspring