Flashcards in Chapter 13 Deck (43)
Living organisms are distinguished by their ability to ...
reproducing offspring that resemble their parents but may look slightly different (demonstrating variation)
shows that offspring differ somewhat in appearance from parents and siblings
the study of heredity and hereditary variation (uniqueness)
Offspring acquire genes from parents by...
inheriting gene on chromosomes
the units of heredity and are composed of segments of DNA
Each gene in an organism's DNA has a ...
specific locus (location) on a certain chromosome
In sexual reproduction,
in terms of genes
we inherit one set of chromosomes from our mother and one set from our father
In asexual reproduction,
one parent produces genetically identical or exact copy (clone) offspring by mitosis
- more simple process
i.e. the multicellular hydra reproduces by budding
In sexual reproduction,
2 parents (produce gametes) give rise to offspring that have unique combinations of genes inherited from the two parents
Fertilization and meiosis alternate in...
sexual life cycles
is the generation-to-generation sequence of stages in the reproductive history of an organism
in humans, each somatic cell has...
made up of 2 sets, one from each parent
an ordered, arranged, visual representation of the chromosomes in a cell that can be used to determine their homology or similarity
Homologous chromosomes (autosomes)
a pair of chromosomes that have the same characteristics
humans have 22 autosome pairs
the transmission of genes on chromosomes and their traits from one generation to the next
distinct from each other and are represented as X and Y
determine the "sex" of an individual
XX = female
XY = male
has 2 sets of each of its chromosomes and a human has 46 chromosomes (2n=46)
where n = the number of single set chromosomes
the number of single set chromosomes
sperm and ova (gametes)
have only one set of chromosomes
In a cell in which DNA synthesis has occurred...
the chromosomes are duplicated and consist of 2 identical sister chromatids
unlike somatic cells, gametes only contain 1 set of chromosomes
variety and the production of new cells that are genetically distinct
cells produce non-identical daughter cells that are used in reproduction
cells contain genes
at sexual maturity, the ovaries and testes produce haploid gametes by this process
Forming a Diploid Zygote
during fertilization, the gametes, sperm, and ovum fuse forming a diploid zygote that develops into an adult organism
3 main types of sexual cycles differ in the ...
timing of meiosis and fertilization
meiosis occurs during gamete formation and the gametes are the only haploid cells
plants and some algae exhibit...
an alternation of generations where the life cycle includes both diploid (sporophyte) and haploid (gametophyte) multicellular stages
in most fungi and some protists, meiosis produces
haploid cells that gives rise to a haploid multicellular adult organism that carries out mitosis, producing cells that will become gametes
haploid multicellular organism
predominant phase in plants
diploid multicellular organism
predominant phase in animals/humans