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Science grade 9 > Chapter 3 > Flashcards

Chapter 3 Flashcards

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Biology 101 flashcards
1
Q

What are sex cells

A

Also known as gametes, they have the chromosome of the parent cell. They make up a small part of the body

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2
Q

What are male gametes called

A

Sperm

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3
Q

What are female gametes called

A

Egg or ovum (ova plural)

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4
Q

What is meiosis

A

Process that produce gametes is called meiosis

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5
Q

Where does meiosis take place

A

Only in cells that produce gametes(reproductive cells)

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6
Q

Why is meiosis sometimes referred to as reduction deduction

A

Because it reduces the number of chromosome by half

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7
Q

What are haploid cells

A

Cells with half the chromosome number of the parent

Symbolized with a “n”

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8
Q

What are diploid cells

A

Cells with a complete set of chromosomes

Symbolized as 2n

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9
Q

What are homologous chromosomes

A

Diploid somatic cells have their chromosome arranged in pairs. Each chromosome has a corresponding one ,forming a pair. The pairs of corresponding chromosomes are called homologous chromosomes
Comes from parent
Each contributes half

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10
Q

What are somatic cells

A

Body cells that reproduce by cell division and make up the vast majority of the organisms cells
Has 23 pairs of chromosomes

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11
Q

What are the 2 stages of meiosis

A

Meiosis I and meiosis II

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12
Q

What is the end result of meiosis

A

4 haploid gametes

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13
Q

Explain meiosis I

A

Similar to mitosis during interphase and prophase
During interphase , chromosomes replicate to form joined sister chromatids
During prophase , chromosome shorten and thicken and become visible
Homologous chromosomes pair up along the equator during metaphase of meiosis I
During anaphase in meiosis I, the pairs of homologous chromosomes separate and move to opposite poles along with their sister chromatids .
Results in two daughter cells but each only has only one homologous chromosome with its sister chromatids still attached

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14
Q

Do sister chromatids separate in meiosis I

A

no

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15
Q

Explain meiosis II

A

sister chromatids in the 2 daughter cells line up at the equator of the cell Each chromatid is pulled to the opposite pole
The nuclear membrane reforms, cytokinesis occurs and results in 4 haploid cells called gametes

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16
Q

Tell some of the differences between mitosis and meiosis

A

In mitosis , sister chromatids separate during anaphase while in meiosis the sister chromatids separate in meiosis II
Mitosis results in 2 diploid cells while meiosis results in 4 haploid cells

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17
Q

What is fertilization

A

The joining or fusion of two gametes

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18
Q

What is a zygote and how is it formed

A

Zygote is the first diploid cell of the offspring and is produced by fertilization

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19
Q

How does the zygote increase in size

A

cell division

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20
Q

Will each new cell have the same DNA as the zygote

A

yes

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21
Q

what is diversity and what causes it

A

Vast amount of variation between species because of sexual reproduction because of homologous pairs

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22
Q

What are alleles and give examples

A

Different forms of the same gene

for example; eye colour, hair line and thumb

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23
Q

How does having homologous pairs produce variations in the gene

A

The corresponding gene for each chromosome might be slightly different .

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24
Q

When will a recessive allele be expressed

A

when both chromosomes contain the recessive allele

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25
Q

When will a dominant allele be expressed

A

when present

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26
Q

What is expressed if the chromosome has both a recessive allele and a dominant allele

A

dominant allele

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27
Q

What is incomplete dominance and give an example

A

Is when neither one of allele gets to be dominant
the two different alleles produce a mixture of traits for example red carnations give pollen to white carnations to make pink carnations

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28
Q

what is codominance and give an example

A

when both traits are expressed in one individual
for example if a parent animal has red hair and the other has white , then the animal will have a roan colored coat
mixture of white and red

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29
Q

Are some characteristics controlled by more than one gene or are have more than two alleles . If so give an example

A

yes like eye colour

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30
Q

What is the difference between sexual and asexual reproduction

A

asexual need one parent while sexual needs 2

asexual reproduction can produce many identical offspring while sexual produce less and genetically different offspring

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31
Q

give one advantage and one disadvantage of sexual reproduction

A

Advantage is the variation helps them adapt to the changes in the environment and survive
Disadvantage is that it is slow and requires two parents

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32
Q

give one advantage and one disadvantage of asexual reproduction

A

advantage is that it is faster and if the parent is successful in one environment then so is the offspring since genetically identical
disadvantage is that if the environment changes , all are affected so less chances of survival

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33
Q

what is conjugation and explain the process .

give examples

A

occurs when two unicellular organisms transfer their gentic material
It happens in bacteria and some protists like paramecium
In conjugation, one cells copies an extra piece of its DNA, called a plasmid, and transfers the plasmid copy to another cell through the mating bridge
They then reproduce asexually by binary fission

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34
Q

How does binary fission help unicellular organisms

A

Increases diversity

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35
Q

What is a hermaphrodite

A

an organism that produces both male and female sex cells in the same individual

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36
Q

What is the advantage of a hermaphrodite

A

Can mate with any other member of its own species and this make sexual reproduction easier

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37
Q

Give 2 examples of hermaphrodites and their process of reproduction

A

Earth worms produce both egg and sperm. When they encounter other earthworms , they exchange sperm with them. Sperm is stored in a special sac till eggs are ready . Fertilization takes place in the worm and each lays eggs

Aquatic hermaphrodites like sponge and barnacles are fixed at one location. They produce egg and sperm at different times so that when the ocean current comes , the sperm doesn’t accidently fertilize their own eggs as the result would be clones

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38
Q

Are flowers hermaphrodites

A

yes

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39
Q

What is the male reproductive structure in a flower

A

stamen

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40
Q

What is female reproductive structure in a flower

A

pistil

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41
Q

what is stamen made of

A

filament which is a stalk that supports the anther

42
Q

Where is the anther and what does it do

A

At the top of stamen and produce pollen

43
Q

Where are the male gametes in a flower found

A

In the pollen grains

44
Q

What are sepals

A

tiny leaf like structures that protect the flower while it is in bud stage

45
Q

Where is stigma and what do it do

A

Top of the tube like pistil and it receives a pollen grain since is sticky

46
Q

What does the tube like style do

A

transfers the pollen grain from the stigma to the ovary

47
Q

where are the eggs contained

A

ovary

48
Q

What are petals and their function

A

coloured leaf like structures of flowers. Attracts pollinators

49
Q

What is pollination

A

the process in which sperm cells(in the pollen) move to egg cells(in the ovary)

50
Q

What are the two types of pollination and explain

A

In cross pollination , pollen is moved from the male structure of one flower to the female structure of another flower by using wind, insects , bird or mammals

In self pollination , the pollen produced a flower can pollinate other flowers on the same plant

51
Q

what follows pollination

A

fertilization

52
Q

Does the zygote or fertilized egg develops into a seed in the ovary of the flower

A

yes

53
Q

What are the two methods of fertilization in animals with separate sexes

A

External and internal fertilization

54
Q

What happens in external fertilization and give examples

A

the sperm and the egg unite outside the body
Fish is an example
the female release her eggs in the water . then male releases his sperm over the eggs and produce a zygote

55
Q

how is external fertilization risky and how do the animals compensate for it

A

The gametes and zygote both are vulnerable to predators and the environment. To ensure survival, thousand of eggs and sperm are released

56
Q

What is internal fertilization and give an example

A

Sperm of the male is deposited inside the female using specialized reproductive structures .
Example is some aquatic animals and most land animals

57
Q

What is an embryo

A

When the zygote divides using mitosis, it forms an embryo

It is the developing organism

58
Q

How are embryo protected

A

when inside the seeds, eggs or the mother

59
Q

In plants ,what does the seed contains

A

embryo and stored food

60
Q

In plants , what does the ovary becomes

A

Fruit

61
Q

What is the egg called once it is fertilized

A

a seed

62
Q

what nourishes the plant until photosynthesis

A

stored food in the seeds in form of starch

63
Q

From which 3 seeds does most of the world’s food comes from

A

corn , rice and wheat

64
Q

What are cotyledons

A

seed leaves

65
Q

What are dicotyledons and example

A

seeds with 2 seed leaves like bean plants

66
Q

What are monocotyledons and example

A

seeds with only one seed leaves like corn

67
Q

do the seeds use the food in the cotyledon when they germinate

A

yes

68
Q

what is radicle

A

part of embryo that will develop into the roots

69
Q

What does the epicotyl become

A

stem and the leaves

70
Q

In corn seed , what supplies food

A

endosperm

71
Q

in beans , what protects the epicotyl

A

the hypocotyl pushes up through the soil and protect the epicotyl

72
Q

do cotyledons drop as the first leaves develop

A

yes

73
Q

What is protecting the embryo in eggs

A

eggshell, jelly substance or an egg casing

74
Q

What is an amniotic egg and give examples of some animals that lay them

A

Eggs of reptiles and birds

An amniotic eggs contains a single embryo surrounded by a shell

75
Q

Name the structures of an amniotic cell

A

yolk sac, allantois, chorion , amnion , embryo , albumen and air space

76
Q

What is the purpose of the yolk sac

A

stores food for the embryo

77
Q

What is the purpose of the allantois

A

holds the waste produced by the embryo

78
Q

What is the purpose of the chorion

A

controls the movement of the gases and waste in and out of the egg so does the allantois

79
Q

What is the purpose of the amnion

A

a fluid filled sac which cushions the embryo

80
Q

What is the purpose of the the albumen

A

cushions the embryo and is an additional food source

81
Q

how do birds protect their eggs

A

they incubate them(keep at a certain temp by sitting on them) to develop them

82
Q

how do reptiles protect their eggs

A

lay and abandon eggs in a climate that will develop them

83
Q

What are monotremes and their 3 species

A

mammals that lay eggs
duck bill platypus
two types of spiny ant eaters

84
Q

What are marsupials and examples

A

have embryos that do not develop inside the mothers uterus .
the young are born . they leave the birth canal , climb through the mom’s fur and enter a pouch where they attach to a nipple of the mammary gland. They grow and develop their
examples are kangaroos, koalas and opossums

85
Q

What are placental mammals

A

embryos develop inside the mammal

86
Q

What is placenta

A

organ that develops around the fetus and connects to the mother

87
Q

What connects the fetus to the mother and what is its function

A

the umbilical cord carries the waste out of the fetus and nutrients to the fetus

88
Q

Explain selective breeding and give an example

A

In selective breeding 2 plant or animals of one species that have desirable traits are bred with each other . The breeder then selects the offspring with desirable traits and breds it with other offspring with the same desirable traits . After several generations , all the offspring will have this trait . Example canola plants and beef cattle

89
Q

Explain artificial vegetative reproduction and give examples

A

Uses plants ability to reproduce vegetatively
produces clones
Individual cells from desirable plants are removed and placed in petri dishes with nutrients and growth hormones . Once they have roots , they are planted in soil

90
Q

Explain grafting

A

Takes a branch from a desirable fruit tree and attach it to the trunk of another tree that has excellent roots but poor fruit. This produces varieties of fruits

91
Q

What is artificial insemination

A

used in agriculture to fertilize domestic animals
used by people when trouble conceiving
sperm collected from desired male and frozen , then inserted in female vagina after ovulation days

92
Q

Explain In Vitro fertilization

A

The sperm and several eggs are collected from male and female animals and fertilization occurs in petri dish
Once eggs are fertilized they can inserted in many different females to grow

93
Q

What is an advantage of In Vitro fertilization

A

Produces many more embryos than naturally produced

94
Q

What do fish hatcheries do

A

If the male and female are caught before spawning , their eggs and sperm are collected and mixed together in a container . Then the fertilized egg is incubated until they hatch and then released

95
Q

What are surrogate mothers

A

Not genetically related to the embryo

96
Q

What is recombinant DNA technology

A

Involves combining genes from different individuals or species into a single molecule of DNA
Human growth hormone to cure dwarfism is now extracted from bacteria with recombinant DNA instead of the pituary glands of dead people

97
Q

What are GMO’s

A

Genetically modified organisms

98
Q

Why are many food crops genetically modified

A

to resist spoilage
resist disease
delay ripening
more nutritional content

99
Q

What are some concerns related to GMO’s

A

can their modifications to wild populations
will their be any original organism left
who owns them

100
Q

Give examples of GMO’s

A

corn and pigs

Science grade 9 (5 decks)

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