Amanda's Week 4 Handout

Week 4 Handout

A03: Amanda Rajapaksa [email protected] OH: M 3-4@CLICS /by

appt. Polyploidism: Ploidy refers to the number of homologous sets of chromosomes in a biological cell. Plants are more tolerant of polyploidism than animals. Plants such as sugar cane, tobacco and cotton are bred to be polyploids because an increase in ploidy almost always results in increased ________. Polyploid plants are often larger and have larger component parts than their diploid relatives. Plants with odd ploidy # (3N, 5N, etc) have no problem going through mitosis but have difficulty going through ______. This is because sexual reproduction requires pairing of the homologous chromosomes. Plants with odd ploidy #s are often ________. Q: Give an example of a common odd-ploidy plant. Name some of the advantages of having an odd-ploidy plant.

Q: How can you form a triploid?

Tetraploids can be formed by treating meristematic cells with ________. This antitubulin agent disrupts the formation of the spindle fibers and prevents prevents normal chromosome segregation. This results in embryos with double the normal usual number of chromosomes. Colchicine can also be used in monoploids to _______________. Autopolyploids have multiple chromosome sets originating from ____ species, and allopolyploids have sets from ______ different species.

Transposable Elements: Q: What is a transposable element?

Transposable elements are a fundamental feature of all organisms and are responsible for creating a lot of genetic variability. Transposons make up 45% of the human genome and 50-80% of large plant genomes. There are two main classes of transposable elements. Class I elements, also known as _____________, transpose via ___________ and encode enzymes like reverse transcriptase and integrase. Class II elements, also known as “cut and paste” DNA-type

transposons, transpose using ____________. They are able to transpose using an ____________ which is responsible for excision and integration. Q: How does transposase function?

Q: Name three features that are common to all Class II transposons. Q: What is the difference between autonomous and nonautonomous members?

Meristems: Q: Define meristems.

The elongation of the plant, also known as ___________, is governed by the _____________. This type of growth occurs in both herbaceous and perennial plants. The width-wise expansion of plants, seen primarily in perennial plants, is known as _____________; this type of growth is due to the lateral meristem, which is also known as the ______________. The vascular cambium is the source of both ____________ and _______________, which make up the plant vascular system. The plant vascular system integrates the root and shoot systems. Q: Which type of vascular tissue (xylem, phloem, both or neither)? ___ Responsible for the transport of water and nutrients within the plant. ___ Made up of two cell types: sieve-tube member and companion cell. ___ The cells that make up this part of the vascular system are alive at maturity. ___ Transports material from the roots to the shoots. ___ Transports material from the leaves to the roots (and everywhere else that needs sugar). ___ Made of long columns of tracheids and vessel elements. ___ Is meristematic.

___ Made up of cells that are lignified (dead at maturity). ___ Transports photosynthates in the plant.

Flower Structure: Flowers are universal among angiosperms. The four main parts or whorls of the flower are as follows: ______, ______, _______, and ________. Q: Define a perfect flower. Q: Define a complete flower. What is a carpellate flower? A staminate flower?

Q: What is the term to describe when both staminate and carpellate flowers are found on the same plant?

Genetics and Flower Development: The ABC model of flower development in angiosperms summarizes how the presence or absence of different classes of genes regulates the development of floral organs. Each protein coded by these genes contains a _____________ that allows the protein to bind to DNA and to function as a regulator in DNA transcription.