Chapter 3 Flashcards
1
Q
What two types of cells do multicellular organisms have that reproduce sexually?
A
- Somatic cells (Body Cells) Diploid, sex cells (Games)
Haploid
2
Q
What are gametes?
A
- Gametes = sex cells
• Half the chromosomes of parent cell and are tiny
fraction of all cells
3
Q
What are the two gametes?
A
- Sperm and egg/ova
4
Q
How many chromosones are among a species?
A
- Animals among a species: equal # of chromosomes
5
Q
How sexually reproducing organisms maintain the same number of chromosomes?
A
- Meiosis
6
Q
What is meiosis?
A
- Meiosis = Type of cell division that results in 4 daughter
cells with 1/2 chromosome # of parent cell.
• Happens only in the cells that produce gametes;
reproductive cells
• Sometimes called reduction division: It reduces
chromosome # 1/2.
• Two phases: Meiosis I + II
7
Q
What happens in meiosis I?
A
- Contains prophase, metaphase, anaphase, telophase
• Results in 2 diploid daughter cells w. = chromosomes
as the parent cell; each has one homologous
chromosome
• Sister Chromatids stay together
• Prophase: Chromatids shorten + thicken, visible
with light microscope
• Metaphase: Homologous chromosomes line up in
middle joined with their sister chromatids
• Anaphase: Pairs of homologous chromosomes
separate and move to opposite poles along with their
sister chromatids
8
Q
What happens in meiosis II?
A
- Contains metaphase ii, anaphase ii, telophase ii
• Metaphase II: Sister chromatids lineup at the equator.
• Anaphase II: Sister Chromatid pulled to opposite poles
+ separated.
• Telophase: Pinching and cytokinesis occurs,
nuclear membrane starts to reform
9
Q
What are cells that have 1/2 chromosome #?
A
- Haploid cells
10
Q
What are cells that have full chromosomes #?
A
- Diploid cells
11
Q
How many chromosomes do humans have?
A
- 46 chrosones/23 pairs.
12
Q
What happens during interphase?
A
- Chromosomes replicate to form sister chromatids.
13
Q
What are homologous chromosomes?
A
- A pair of corresponding chromosomes
• The gene on one of the chromosomes in the pair
correspond to the other genes on the other
chromosomes in the pair.
• Each parent contributes one-half of chromosomes.
14
Q
What is the joining or fusing of two gametes?
A
- Federalization
15
Q
What happens in fertilization?
A
- The sperm would fuse into an egg to form a zygote?
16
Q
What happenes to a zygote after fertilization?
A
- It reproduces through cell division/mitosis
• Each new cell will contain the same genome as the
zygote
17
Q
What produces variation among members of the same species?
A
- Homologous chromosomes.
18
Q
What are the different forms of the same gene called?
A
- Alleles
19
Q
- How many alleles can be contained for the same type of gene?
A
- Two
20
Q
- What is a dominant allele?
A
- An allele that will express its trait if it is present.
21
Q
- What is an recessive allele?
A
- An allele that will only be expressed if both
chromosomes contain the recessive allele
22
Q
- What if an individual has one of each allele?
A
- The dominant allele is expressed
23
Q
- What is an incomplete dominance?
A
- When two different alleles produce a mixture of a trait
24
Q
- What is codominance?
A
- When both traits are expressed in one individual.
25
- How many alleles are contributed to a child?
- Each parent contributes only one of its two alleles ni its
sperm cell or egg cell.
26
What are the advantages of sexual reproduction
- The offspring is genetically different from their parents
• This variation allows individual organisms to
adapt to changes in the environment.
• They can then reproduce and pass on the traits that
helped them survive to their offspring.
- In outbreaks, some humans who are exposed to a
disease can fight it. They can reproduce and pass on
their ability to fight the disease to their children
27
What is a disadvantage of sexual reproduction?
- The individual needs to find a mate.
• Also tends to produce fewer offspring than asexual
reproduction and can be a lot slower.
• Most organisms that reproduce sexually have to grow
and develop before they start to produce gamest
28
What is an advantage of asexual reproduction?
- If a parent does well in its environment, the offspring
will also do well in the same environment because the
offspring are genetically identical to the parent.
- Only one parent is necessary
- The parent does not need to find a mate
- They can reproduce very rapidly
• Bacterium living in a good environment can
reproduce every 20 minutes.
29
What is an disadvantage of asexual reproduction?
- Offspring cannot adapt to the environment as they are
genetically identical
• The offspring will be affected the same way as the
parent
30
What is conjugation?
- When two unicellular organisms transfer or exchange
some of their genetic material
• Organisms that can reproduce asexually by binary
fission can also reproduce sexually by conjugation
• Only occurs in some bacteria and certain protists,
such as paramecium
• The details of conjugation are slightly different in
different species
• Conjugation increased the diversity of individuals in
unicellular species
- May be a factor that helps some bacteria to become
resistant to antibiotics
31
How does E.Coli use conjugation?
- In E.coli, one cell copies an extra piece of its DNA,
called a plasmid, and donates the plasmid copy to
another cell
• Both the daughter cells then reproduce asexually
by binary fission
• The offspring they produce contain the same
amount of DNA as the parent
32
What are hermaphrodites?
- An organism that produces both male and female sex
cells in the same individual
• Hermaphrodite can mate with any other member of
their species to produce offspring
33
Why are species hermaphrodites?
- Because plants and some animals are attached to one
location throughout their life and rarely come in
contact with other members of their species. To get
around this situation, species become hermaphrodites
to allow them to reproduce with any other member of
their species.
34
How do earthworms reproduce?
- Two earthworms attach, exchange sperm, and then
seperate
• The sperm cells are stored in a special sac until the
eggs are ready
• Within a few days, fertilization takes place in a in a
mucus ring secreted by the clithellum, the thickened
band on a earthworm
- The ring becomes a cocoon for the fertilized eggs
and slips off in the soil.
• The baby earthworms hatch about a week later
35
How do hermaphrodite organisms prevent the their sperm from fertilizing their own eggs?
- They produce sperm and eggs at different times
36
How do aquatic hermaphrodites such as sponges and barnacles reproduce?
- In sponges, the sperm are released into the water and
are carried by water movement to other sponges
• Fertilization occurs internally after the sperm enters
the sponge's central cavity through tiny pores
- The baby sponges called larvae are mobile and are
released into the water
• They swim to other locations, anchor themselves
to the bottom, and grow
- Barnacles have a penis, which extends into a
neighbouring barnacle to deposit the sperm
• The barnacle larvae are expelled into the water and
are carried by water currents to other locations
37
What is a flowers male reproductive system?
- The male reproductive structure is the stamen
• The stamen is made of the filament, a stalk that
supports the anther
• The anther is the top of the stamen and produces
pollen
- Pollen grains contain the male gametes (Sperm)
• There are usually several stamens on each flower
38
What is a flowers female reproductive system
- The female reproductive system is the pistil
• The top of the pistil is the stigma
- The sticky stigma receives a pollen grain which will
travel down the style to the ovary, were the eggs are
contained
39
Which flower structures surround the female and male structures?
- Petals and the stamen
• Petals are the coloured leaf-like structures of most
flowers
- The organisms that pollinate flowers are attracted to
the coloured petals
• Sepals are tiny leaf-like structures that protect the
flower while it's in the bud stage
- Sepals are located at the base of the flower where it
joins the stem
40
How do flowers reproduce
- Flowers reproduce by cross-pollination or by self-
| pollination
41
What is pollination?
- The process by which pollen is moved from the male
structures to the female structures
• Pollination occurs in a variety of ways
42
What is self-pollination?
- Self pollination is when the pollen produced by a
| flower can pollinate other flowers on the same plant
43
What is cross-pollination?
- Cross pollination is when pollen is moved from the
male structure of one flower to the female structure of
another flower by wind, insects, birds, or mammals.
44
What are separate sexes?
- When an species have separate female and male
individuals
• In animals that have separate sexes, there are two
methods of fertilization: external fertilization and
internal fertilization.
45
Do all flowers have female reproduce structures in the same flower
- No
• Conifers, such as pine and fir trees, have separate
male and female cones on the same plant
• Some species have separate male and female
flowers on the same plant
• Other species, such as poplar trees, have separated
male and female flowers on separate plants
46
What is external fertilization?
- The union of the egg and sperm outside the body
• Occurs in many aquatic animals
- For salmon, and many other aquatic animals, the
female releases her eggs into the water and the
male then release his sperm over the egg
• Hundreds or even thousands of eggs and sperm are
produced to ensure that enough will unite and grow
to be adults
• Both the gametes and the developing young are
vulnerable to environmental conditions and predators.
47
How do coral reefs reproduce?
- Coral reefs are made of millions of tiny animals, called
corals
• Each animal builds a hard shell
- These shells fuse together to make up a reef
• Reproduction occurs when the males and the
females both release their eggs and sperm into the
ocean at the same time.
- Fertilization is by chance, as millions of tiny cells fill
the water and are carried by the movement of the
water
48
What is internal fertilization?
- The union of the egg and sperm inside the body
• Some aquatic animals, such as sharks, and most
terrestrial land animals require the sperm from the
male to be deposited inside the body of the female
• Animals have specialized reproductive structures to
accomplish this
49
When a zygote divides, what does it become?
- It becomes a embryo
50
What is a embryo?
- A developing organism
51
How are embryos protected?
- Embryos are protected when they develop inside
| seeds, eggs, or the mother.
52
In plants, what does the ovary become?
- The fruit
53
What is a seed?
- An egg that has been fertilized in the ovary of the
| flower
54
What does the sed contain?
- The embryo, as well as stored food
55
What is the purpose of the food contained inside the seed?
- The food nourishes the developing plant until it is able
| to produce its own food using photosynthesis
56
What is the type of food found in the seed?
- Starch or sugar
57
Where does most of the world's food come from?
- Most of the worlds food comes from the seeds of three
| plants: corn, rice, and wheat
58
What compound surrounds the seed in some fruit?
- Sugar
59
What are the two types of seeds produced by flowering plants?
- Bean seeds and corn seeds
60
What are bean plants and corn plants called?
- Corn plants are called monocotyledons because they
produce seeds with only one cotyledon,
- Bean plants are called monocotyledons because they
produce seeds with only one cotyledons.
61
What is a cotyledon?
- Cotyledons are seed leaves
• They supply food to bean seeds
- The cotyledons get smaller as the embryo grows
and the food is used up
62
What is the radicle?
- The part of the embryo that will develop into the roots
63
What is the endosperm?
- The structure that supplies food to corn seeds
64
What is the epicotyl?
- The structure that becomes the stem and the leaves
65
What is the hypocotyl?
- The structure that pushes up through the soil and
protects the epicotyl
• Found in corn seeds
66
What are eggs?
- A female gamete; a structure produced by some
| terrestrial animals to protect the developing embryo
67
What are layed eggs?
- A vast majority of animals lay eggs
• Eggs that are laid contains the zygote, some nutrients,
and a mechanism for protection, such as a shell, a
jelly-like substance, or an egg case
68
How do laid eggs vary across species?
- Some animals, such as tapeworms, produce a single
egg case that contains thousands of embryos
- The eggs of reptiles and birds contain a single embryo
surrounded by a shell
• This type of egg is called an amniotic egg
69
What are the structures of the eggs?
- The albumen, embryo, amnion, yolk sac, chorion,
| allantois
70
What is the function of the albumen?
- The albumen also cushions the embryo and is an
| additional source of food
71
What is the function of the amnion?
- The amnion cushions the embryo, and it is a fluid filled
| sac
72
What is the function of the yolk sac?
- The yolk sac stores food for the embryo
73
What is the function of the allantois?
- The allantois hold waste produced by the embryo
• It controls the movement of gases and waste in and
out of the egg
74
What is the function of the chorion?
- The chorion, along with the allantois, controls the
| movement of gases and wastes in and out of the egg
75
How do birds take care of their eggs?
- They keep their eggs warm by sitting on them or
| insulating them with their feathers
76
How do sea turtles take care of their eggs?
- Sea turtle mothers dig a hole in the sand, lay the eggs,
bury them and leave
• When the eggs hatch, the hatchlings must dig their
way to the surface and then crawl down the beach to
the ocean
- Many do not survive
77
How do adult parasitic tapeworms take care of their eggs?
- Adult parasitic tapeworms live in the intestines of
animals
• They release egg cases that contain thousands of
eggs
78
How do the eggs of the tapeworm get back into the body of an animal?
- The egg cases break open, and the eggs are
released into the grass in the feces of the animals
• The eggs are protected from drying out, but may
be eaten by other grazing animals
- The eggs that are eaten will travel to the
intestines, where they will develop into adults
and feed on digested matter
79
What are mammals that lay eggs called?
- Mammals that lay eggs are known as monotremes
• There are only three living species of spiny anteater:
the duckbill platypus and two species of spiny
anteater
80
What are the only living mammals that lay eggs?
- There are only three living species of monotremes:
the duckbill platypus and two species of spiny
anteater
81
Where does the only living mammals that are monotremes exist?
- All the species live either in the continent of Australia
| or on the island of New Guinea
82
How does the duckbill platypus take lay/care of its eggs?
- The platypus lays its eggs in burrows and incubates
them until they hatch
•
83
How do both species of spiny anteater lay/take care of their eggs?
- The spiny anteater lays its eggs in its pouch, where
| they are incubated
84
What are marsupial organisms?
- Marsupial organisms include kangaroo, koalas, and
opossums
• The embryos don't develop for long in the uterus,
so the young are born tiny and immature
- The young climb from the birth canal through the
mother's fur into a pouch, were they attach to a
nipple of a mammary gland
• Even after they are mature enough to leave the
pouch, they return to it for feeding and security
85
What are placental mammals?
- The embryo's of placental mammals, such as humans,
develop inside the mother for much longer than the
embryos of marsupial mammals
• The word placental comes from the word placenta
86
What is the placenta?
- The placenta is the organ that develops around the
fetus and connects to the mother
• The fetus is attached to the placenta via the umbilical
cord
87
What is the umbilical cord?
- The structure that carries waste out of the fetus and
| nutrients into the fetus inside of the placenta
88
What is selective breeding?
- In selective breeding, two plants or two animals of one
species that have desirable traits are bred with each
other.
• The breeder than selects the offspring that show the
desirable traits of the parents and breeds them other
individuals with the same traits
• After selectively breeding individuals over several
generations, all the offspring will have the desirable
traits
89
What are organisms that have been used in selective breeding?
- Beef cattle
• Selectively bred to produce high quality and quantity
muscle (meat)
- Canola plants
• Seeds are used to produce a cooking oil
• Selectively bred to improve the quality of the oil
90
What is the method of cuttings?
- If growers have a plant that has desirable traits, they
can take cuttings from it and grow new plants from the
cuttings
• The drawback to cuttings is that only so many cuttings
can be taken from a plant.
91
What is a better method of producing plant clones?
- Scientists have developed a quicker way to produce
plant clones
• They remove individual cells from a desirable plant
and place them in bottles or Petri dishes that contain
nutrients and growth hormones
- Once the seedlings have grown roots, they are
planted in soil
• Advantage: More clones can be produced and an
faster process
92
What is grafting?
- Grafting involves attaching a branch from a desirable
tree onto the trunk of another tree that may have
excellent roots but poor fruit
• The bark of the grafted branch will fuse with bark of
the root tree
- The branch will grow and eventually produce fruit
93
What plants often use grafting?
- Fruit trees; apples, grapes, and peaches
94
What is artificial insemination?
- A veterinarian collects sperm from a male animal and
inserts it into a female animal of the same species.
• This technique is used extensively in agriculture to
breed domestic animals with desirable traits
95
How is artificial insemination used?
- Most dairy cows are conceived using artificial
insemination
- Used in zoos to maintain or increase the population of
endangered species
• In both cases, sperm is collected from the desired
male and frozen. It is then transported to female
animals in far away farms or zoos
• Thus, sperm of one champion bull can fertilize the
eggs of many cows in different locations
96
What is In Vitro fertilization?
- A process that builds on artificial insemination
• The sperm and several mature eggs are collected
from male and female animals with desired traits and
fertilization occurs in a lab, in a petri dish
- Once the eggs are fertilized, the embryos can be
inserted into many different female cows.
• These cows are surrogate mothers because they
are not genetically related to the embryo as the
eggs are fertilized from bull sperm
97
What is the advantage of In Vitro fertilization?
- The advantage of in vitro fertilization is that it produces
many more embryo.then what would be produced
naturally
98
What does "In Vitro" mean?
- "In Glass"
99
What are fish hatcheries?
- Fish hatcheries use technology to ensure a higher rate
of survival in wild fish populations
• For example, wild salmon use external fertilization,
which means that relatively few eggs are actually
fertilized.
• This process produced a much greater number of
young salmon then would occur naturally
100
How are wild salmon used in fish hatcheries?
- Just before they are ready to reproduce, male and
female fish are caught.
• The eggs and sperm are collected and mixed
together in a container
- The fertilized eggs are incubated in special trays
that have a constant supply of cold running water
• Once the eggs hatch, the young are fed at the
hatchery before they are released into the wild
101
What is recombinant DNA technology?
- Recombinant DNA technology involves combining
genes from different individuals or different species
into a single molecule of DNA
• Bacteria that contain recombinant DNA produce it
- They are most commonly used to produce drugs,
including insulin for diabetics and vaccines to
prevent hepatitis b and to treat some forms of
dwarfism
102
How is recombinant DNA technology used to treat human dwarfism?
- Human growth hormone was originally extracted from
the pituitary glands of dead people
• Now bacteria that contain recombinant DNA produce
it
• The human gene that codes for growth hormone is
inserted into a bacterial cell
- The bacterium incorporates the new strand of DNA
into its cytoplasm as a plasmid
• This new genetic material directs the bacterial cell
to produce human growth hormone
- Through cell division, the new DNA is replicate in
millions of daughter cells. Each daughter cell
produces human growth hormone
• The growth hormone is then collected
103
What is Genetic Engineering?
- A process that involves intentionally altering an
organism's genes
• Many food crops have been genetically modified to
resist spoilage or disease, to delay ripening, or to
improve their nutritional content
104
What is a GMO?
- Genetically modified organism
105
What are some controversies to GMO?
- That GMo could pass their DNA to wild populations
and produce super-organisms and also raises the issue
of who owns these new organisms
- GMO can be a risk to eat as they have genes from
other species
