Midterm Exam Flashcards
define a gene
a segment of DNA
define alleles
different forms of a gene
define homozygous
2 alleles are the same
define heterozygous
2 alleles are different
define genotype
specific alleles on a chromosome
define phenotype
physical and behavioral traits produced from genotypes
define genetic drift
a change in allele frequencies of a population caused by chance environmental effects
define population bottleneck
occurs when a population undergoes a drastic reduction in population
define founder effect
occurs when isolated populations are founded by a small number of individual organisms
Does genetic drift have a bigger influence on small or large populations?
small populations
define heterozygosity
the number of heterozygous alleles in a population
define inbreeding depression
negative effect of homozygosity on fitness
What is the extinction vertex?
a phenomenon where a small population loses heterozygosity over time, trapping their population where it will slowly become extinct
natural selection is about selecting…
for traits that are need for survival and reproduction
define fitness
individuals ability to survive and reproduce
define adaptations
traits that increase an organisms fitness
what is the end result of natural selection?
adaptation of environment via changes in genetic frequency
define autotroph
self feeder; creates own food through photosynthesis
define cellulose
large polysaccharide molecule of glucose
define angiosperm
flowering plant
define tracheid’s
tapered specialized cells that conduct water and provide support
define monocotyledon
single cotyledon in the seed
parallel veined leaves
define dicotyledon
2 cotyledon in the seed
netted leaf vein systems
define cotyledon
food storage organ
what are the 3 main activities of a plant?
- transport of material
- seed production
- food storage
Primary and secondary cell wall are categorized by?
permeability and rigidity
describe parenchyma cells
unspecialized
thin primary cell wall and NO secondary cell wall
parenchyma’s function
photosynthesis, food storage, aerobic respiration
describe collenchyma cells
thick primary cell wall and NO secondary cells wall
collenchyma’s function
to support growing parts of a plant
describe sclerenchyma cells
supportive cell
rigid secondary cell walls (lignin)
what is the vascular bundle composed of?
phloem, cambium, and xylem
types of tissues
dermal
vascular
ground
tissues that compose the dermal system
epidermis
cork or bark
tissues that compose the vascular system
phloem
cambium
xylem
tissues that compose the ground system
pith
cortex
define epidermis
single outer layer of cells
define cork/bark
several layer of empty cell wall “bricks”
define cork/bark
several layer of empty cell wall “bricks”
define cork/bark
several layer of empty cell wall “bricks”
phloem characteristics
- food solution for the leaves
- long tubular cells with thin walls
- located towards the outer side of the vascular system
cambium characteristics
- layer of cells between the phloem and xylem
- ONLY found in dicots
- produces more phloem, cambium, and xylem
xylem characteristics
- carries water and mineral from the soil up to the leaves
- located on the inner portion of the vascular system
characteristics of the pith
- central core of tissue in most plants
- usually no longer alive/active
cortex characteristics
- cylinder of several tissue types
- located inside the outer covering of cells
- stores, food, water, and minerals
- replaces the protective outer covering
define prothallus
mass of cells that first grows from a germinated spore
define gametophyte
plant sex cell
define antheridium
male sex portion
define archegonium
female sex portion
define sporophyte
plant seed
What does the male gametophyte in an angiosperm contain?
1 pollen tube nucleus
2 sperm nuclei
define alternation of generations
the observation of a gametophyte as it proceeds to produce haploid gametes that fuse to form a diploid sporophyte
define germinating
when a seed takes on water and begins to sprout
define micropyle
a microscopic hole that permits water vapor and air to enter the interior of the seed
define radical
immature root
define plumule
miniature leaves
define an actinomorphic flower
flowers that are radially symmetrical
define zygomorphic flowers
flowers that can only be but along 1 plane to have equal halves
what makes a perfect flower?
has both male and female reproductive organs on the same flower
root hairs increase
the absorptive surface area of the root
define lenticels
opening in stem to allow for oxygen and carbon dioxide exchange
define node
part of a plant where a leaf, branch, or aerial root grows
define internode
the section of stem between two adjacent nodes
location of the terminal bud
at the end of the stem
axillary bud can develop into
a branch shoot or flower cluster
bud scale scar are and can be used to…
are: left when a bud falls off
used to: track the age of a stem
define stomata
pores found on the leaves surface
define receptacle
swollen base of the flower bud attached to the stem
define calyx
circle of leaf like structures at the base of the flower petals
where are the petals located?
inside the calyx
the pistil is made up of what 3 parts?
- stigma
- style
- ovary
stigma is a…
sticky tip to which pollen will stick to during pollination
the style is where
pollen will germinate to produce pollen tube
ovary is where
fertilization will occur
the stamen consists of what 2 structures?
- filament
2. anther
the filament is a
think stalk
the anther is a
oval tip that produces pollen grains
male and female reproductive structures in angiosperms?
male: stamen
female: pistal/carpal
