Mod 5

Question 1

asexual reproduction in plants

what is the role of spores in the asexual reproduction of fungi?

Answer 1

for the dispersal and reproduction of genetically identical fungi. spores form by meiotic cell divisions

Question 2

sexual reproduction in plants

what is the role of spores in the sexual reproduction of fungi?

Question 3

asexual reproduction in plants

How is budding different from the production of spores

Answer 3

budding is the production of a new individual directly from an outgrowth of the parent cell. Spore production occurs by multiple cell divisions within specific structures

Question 4

sexual reproduction in plants

explain how reproduction in fungi maintains the continuity of the species

IMPORTANT

Answer 4

fungal hyphae are generally haploid. Azexual reproduction maintains this by production genetically identical haploid spores. Sexual reproduction produces a diploid cell with paired chromosomes that undergo meiosis to continue the process of producing haploid cells (spores), which in turn germinate to produce haploid fungi

Question 5

sexual reproduction in plants

compare and contrast asexual and sexual reproductive processess in plants

you can use rhizopus and yeast as an example

Answer 5

in both rhizopus and yeast, haploid gametes form a diploid cell, then undergo meiosis to form haploid spores. However, in Rhizopus this is achieved by specific gamete cells on amture hyphae. In yeast the whole organism/cell fuses with a matching mating type to form the diploid cell before undergoing meiosis.

Question 6

asexuala reproduction in cellular slime moulds

compare and contrast binary fission and multiple fission

Answer 6

binary fission produces two new free living cells from a single division of the nucleus. Multiple fission produces multiple nucleii before the division of the cytoplasm to create multiple new cells.

Question 7

asexual reproduction in plants

What is the purpose of colony formation in protists

can use cellular slime moulds as example

Answer 7

colony formations allow the species to disperse into new areas and produce offspring that can further assist in dispersion

Question 8

asexual reproduction in animals

what is the advantage of fragmentation to an animal with a relatively simple body plan and why wouldn’t this work for more complex animals?

can use the example of a flatworm

Answer 8

fragmentation allows the flatworm to rapidly reproduce and colonise a favourable environment. Injured flatworms are able to regenerate their lost body and are therefore hardy organisms.

Question 9

asexual reproduction in animals

all individuals produced by budding or fragmentation are clones. Explain why this might leave a population vulnerable if environmental conditions rapidly changed

Answer 9

a population consisting of genetic duplicates are less likely to survive changing environmental conditions because of their lack of diversity.

Question 10

asexual reproduction in plants

define vegetative propagation and its purpose

Answer 10

vegetative propagation is any asexual reproduction of plants in which a new plant grows from a fragment of vegetative tissue from the parent plant

Question 11

asexual reproduction in plants

what feature of plant cells favour vegetative propagation

Answer 11

plant cells at the growing tips of the plant are totipotent (essentially stem cells) so can differentiate to form all the tissues of the adult plants

Question 12

asexual reproduction in plants

describe some of the natural means of vegetative propagation in plants

can find explanation in dictionary

Answer 12

rhizomes
stem and root tubers
runners
corms
bulbs
plantlets

Question 13

asexual reproduction in plants

how are plants favoured/not favoured by vegetative reproduction

Answer 13

vegetative reproduction enables a well adapted plant to spread rapidly and saturate its environment. They have a competitive advantage to plants that invest their energy into producing and germinating seeds, as this method allows the plant to invest its resources into growth.

However, vegetative propagation between the plants would be unfavourable when faced with selection pressures such as changing environments due to a lack of genetic variation

Question 14

asexual reproduction in plants

what are the advantages for humans of vegetative propagation

Answer 14

high yeild of the most genetically successful characteristics in plants, use less resources and time for growing and seeding

Question 15

reproduction in ferns (plant reproduction)

what feature distinguishes ferns from seed plants

seed plants are angiosperms and gymnosperms

Answer 15

seed plants produce seeds from which a new plant grows, whereas ferns release spores that produce a prothallus, which in turn grows a fern

Question 16

reproduction in ferns (plant reproduction)

Why do ferms require moist environments in order to reproduce? why does this requirement limit their survival in the long term?

Answer 16

fern gametophytes produce motile sprem cells which must swim using a film of water to the egg cell for fertilisation.
Ferns are limited to area where water is relatively abundant as the prothallus is susceptible to dring out, and the sperm need water to reach the egg. They are therefore not well adapted to drier environments

Question 17

sexual reproduction in angiosperms (plant reproduction)

in which part of a flowering plant do the male/female gametophytes develop

Answer 17

anther/ovule

Question 18

sexual reproduction in angiosperms (plant reproduction)

why don’t angiosperms need a moist environment for fertilisation to occur

Answer 18

the gametes are carried by pollen directly from the male to the female parts of the flower. The pollen is either transported by wind or other organisms.

Question 19

sexual reproduction in gymnosperms (plant reproduction)

how does the sperm cell reach/fertilise the egg in conifers

Answer 19

pollen sticks to a drop of fluid in the micropyle. The fluid evaporates brigning the pollen close to the egg cell. A pollen tube develops and the sperm cell moves through it to the egg cell.

Question 20

sexual reproduction in gymnosperms (plant reproduction)

which structure in a conifer is equivalent to the embryo sac of angiosperms

Answer 20

idfk

Question 21

sexual reproduction in gymnosperms (plant reproduction)

what is the role of wind in the complete life cycle of a conifer

Answer 21

wind transports the male gamete (pollen) to the female gamete (egg cell) for fertilisation

Question 22

asexual reproduction of plant cells

how is budding different from binary fission

Answer 22

With budding, a parent cell creates an outgrowth that eventually becomes a daughter cell. With binary fission, a parent cell reproduces by splitting in half. Both binary fission and budding are asexual, leading to genetically identical cells.

Question 23

animal sexual reproduction

describe one advantage/disadvantage of sexual reproduction

Answer 23

adv - offspring have more genetic diversity, meaning populations of sexual organisms are more likely to survive selective pressures
dis - requires more energy and time to mate/reproduce, more likely to lead to the extinction of a species as they need a mate. fertilisation and embryonic growth are slower than asexual reproduction

Question 24

animal sexual reproduction

distinguish between internal fertilisation and external fertilisation, identifying advantages of each strategies

Answer 24

external fertilisation fertilises eggs outside of the parent. The chance of the fertilisiation is low, but increased by the synchronised release of very large numbers of eggs and sperm (spawning). This also proves a lower risk to the parent organisms.

in internal fertilisation, the eggs are fertilised inside the body of the female by sperm deposited by the male. This increases the chance of fertilisation but carries a higher risk of mortality for the parent organisms.

Question 25

# animal sexual reproduction describle two features of the amniote egg that makes it an ideal adaptation to reproduction on land | eg bird

Answer 25

provides protection from physical damages/dehydration in terrestrial environment provides nutrients and stores wastes for the period of the embryonic development

Question 26

# animal sexual reproduction using examples, distinguish between oviparous and viviparous vertebrates

Answer 26

in oviparous vertebrates, the embryo develeops in the egg after it is laid in viviparous vertebrates, teh young develop inside the mother, deriving nutrients from the parent.

Question 27

# animal sexual reproduction some frogs and toads have evolved novel ways of enhancing the survival of their eggs. provide an example of this | midwife toad or surinam toad

Answer 27

male midwife toad carries eggs, keeps them moist and places them in a favourable habitat to hatch In the Surinam toad, spongy skin on the female's back encloses and protects teh eggs until they hatch

Question 28

# animal sexual reproduction name two vertebrates that produce shelled, waterproof eggs

Answer 28

birds/reptiles

Question 29

# animal sexual reproduction what feature of a vertebrate egg has been primarily responsible for its success

Answer 29

watertight/protective shells that prevent dessication and enables reproduction to be independent of water

Question 30

# animal sexual reproduction explain how a vertebrate egg eliminates wastes for a developing embryo

Answer 30

wastes collect in the allantois where they are stored throughout embryonic development

Question 31

# animal sexual reproduction explain how a vertebrate egg allows gas exchange to a developing embryo

Answer 31

the shell is permeable to gases. Blood vessels in the inner membrane perform gas exchange.

Question 32

# animal sexual reproduction explain how a vertebrate egg provides nutrition to a developing embryo

Answer 32

the yolk is mainly fat and the albumin is mainly protein

Question 33

# animal sexual reproduction describe different ways in which animals can allocate their total reproductive effort

Answer 33

animals can allocate theri reproductive effort to prioritise either the number of young they produce or how well they care for them. If they produce a large number of young, they will not have enough energy for parental care. Many will die but enough will survive. If only a few offspring are produced there is enough energy to care for them and most will survive.

Question 34

# animal sexual reproduction animal care for their offspring can fluctuate depending on environmental pressures. Explain how environmental pressures might influence how much care is provided by each parent

Answer 34

In environments with plentiful resources and low risks, parental care is the task of only one parent. When risks such as selective pressures to the offspring are high, successful rearing of the offspring may require the effort of both parents

Question 35

# animal sexual reproduction why are monotremes, marsupials and placentals all classed as mammals

Answer 35

all have fur, produce milk and are warm-blooded.

Question 36

# animal sexual reproduction why are monotremes regarded as being very primitive mammals

Answer 36

they retain reptilian features ie egg laying and have a cloaca

Question 37

# animal sexual reproduction describe two features of marsupial reproduction that are advancements on the monotreme reproductive pattern

Answer 37

The marsupials bear live young (despite being at a very early stage of development). No cloaca, seperate vaginal opening for birth of young. Suckling occurs from porperly formed teats instead of pores

Question 38

# animal sexual reproduction in what way is the reproductive plan in placentals more highly developed than that of marsupials

Answer 38

young are retained in the uterus to a relatively advanced stage of development before being born. The placenta provides a complete and reliable source of nutrition for the embryo in the uterus.

Question 39

# animal sexual reproduction why do hoofed mammals have longer gestational periods | eg sheep, zebra, cow, horse, antelope

Answer 39

hoofed animals tend to be prey species. They are potentially easy prey when born so must be sufficiently well developed at birth to run from potential predators. Herd animals are also often migratory or constantly moving. The young must therefore be aple to keep up with the herd.

Question 40

# animal sexual reproduction why do sperm need to be motile

Answer 40

sperm must be able to move through the uterus and into the oviducts to reach and fertilise the ovum. They must move quickly to achieve fertilisation as they only live for 48 hours

Question 41

# animal sexual reproduction how does an egg move along the fallopian tube

Answer 41

ova move as a result of the wave like motion of the cilia in the fallopian tube

Question 42

# animal sexual reproduction Why does a mature egg need to be so many times larger than a sperm

Answer 42

because the ova contain nutritional rsources to support and sustain the early development of the embryo. The ova also lives for significantly longer than the sperm and must therefore be larger (?)

Question 43

# animal sexual reproduction describe how eac of the following three features of a sperm cell contribute to its role in reproduction Tail, Mitochondira, acrosome

Answer 43

tail - propels sperm through the female reproductive tract toward the ovum for fertilisation Mitochondria - creates ATP (energy) for movement that is provided by cellular respiration acrosome - contains enzymes to digest the layers surrounding the ovum for fusion of ovum and sperm

Question 44

# animal sexual reproduction What is the main role of the male reproductive system

Answer 44

produce sperm to fertilise its female gamete counterpart

Question 45

# animal sexual reproduction define spermatogenesis and where does it occur

Answer 45

the production or development of mature spermatozoa occurs in the seminiferous tubules of the testes

Question 46

# animal sexual reproduction are sperm cells haploid or diploid? explain

Answer 46

haploid because they contain half of the necessary chromosomes required to make a diploid cell (the egg contains the other half)

Question 47

# animal sexual reproduction describe the difference between the lifetime production of gametes in males and females

Answer 47

males produce sperm continuously throughout their life time. In contrast, females are born with their full complement of eggs, they do not produce any more and ovulate approximately 400 times in their reproductive lifetime.

Question 48

in humans, how might the difference between the lifetime production of gametes in males and females affect the reproductive decisions of a species/pair

Answer 48

females are faced with decisions about reproductive timing and the limited capacity to produce offspring. Males can more ably reproduce throughout their lifetime

Question 49

# animal sexual reproduction describe the difference in the number of gametes produced from the original precursor cell between males and females

Answer 49

from one primary oocyte only one egg is produced (with three polar bodies). From one spermatogonia four sperm cells are produced.

Question 50

# animal sexual reproduction what is the trigger for the completion of oogenesis

Answer 50

fertilisation of ovum by a sperm

Question 51

# animal sexual reproduction where does fertilisation occur

Answer 51

usually in the fallopian tube

Question 52

# animal sexual reproduction identify the hormones responsible for: follicle growth ovulation

Answer 52

FSH surge in LH

Question 53

# animal sexual reproduction - menstruation each month, several ovatian follicles begin development but only one (the graafian follicle) develops fully i) what hormone is secreted by developing follicles in the ovaries? ii) what is the role of this hormone? iii) what happens to the follicles that do not continue developing

Answer 53

i) oestrogen ii) Promotes repair and growth of the uterine lining iii) The follicles are re-established

Question 54

# animal sexual reproduction what is the hormonal trigger for menstruation

Answer 54

a sharp drop in progesterone levels

Question 55

# animal sexual reproduction - menstruation what is the principal hormone secreted by the corpus leteum? what is the purpose of this hormone?

Answer 55

progesterone

Question 56

# animal sexual reproduction briefly decribe the significant events in fertilisation and their importance: i) capacitation ii) the acrosome reaction iii) fusion of egg and sperm plasma membranes iv) the cortical reaction v) fusion of egg and sperm nucleii

Answer 56

i) changes in the surface of the sperm cell (caused by the acidic environment of the vagina) that allow it to stick to the oocyte ii) the release of enzymes from the acrosome at the head of the sperm. These enzymes digest a pathway through the follicle cells and the zona pellucida iii) enables the sperm nucleus to enter the egg. The fusion causes a sudden depolarisation of the membrane that forms a fast block to further sperm entry iv) A permanent change in the egg surface that provides a slow, permanent block to sperm entry. Cortical granules are released into the perivitelline space, followed by the hardening of the viteline layer v) the fusion of nuclei forms the diploid zygote and initiates the rapid cell division that follows fertilisation.

Question 57

# animal sexual reproduction why is it important that fertilisation of the egg by more than one sperm does not occur?

Answer 57

this would result in too many chromosomes in the zygote (non viable offspring)

Question 58

# animal sexual reproduction explain why the egg cell, whern released from the ovary, is termed a secondary oocyte

Answer 58

the oocyte is arrested in metaphase of meisosis II after it has undergone the first meiotic division

Question 59

# animal sexual reproduction At which stage of fertilisation is meitoic division completed

Answer 59

after the formation of the zygote (when sperm and egg fuse)

Question 60

# animal sexual reproduction what contribution do the sperm and egg cell make to each of the following: i) the nucleus of the zygote? ii) the cytoplasm of the zygote?

Answer 60

i) 50 sperm/50 egg ii)0 sperm/100 egg

Question 61

# animal sexual reproduction what is the importance of implantation to the early nourishment of the embryo? what is the purpose of HCG production by the embryo

Answer 61

implantation extablishes close cotact between developing fetus and uterine lining, providing for the early nourishment of the mebryo HCG prevents degeneration of the corpus luteum, so that it ocntinues to secrete progesterone and maintain the pregnancy (placenta takes over this role at 12 weeks)

Question 62

# animal sexual reproduction why is the fetus particularly prone to damage from drugs towards the end of the first trimester?

Answer 62

this is the period when most organ development occurs so the tissues are most prone to damage from drugs

Question 63

# animal sexual reproduction why is the corpus leteum the main source of progesterone in early pregnancy

Answer 63

to maintain the endometrium before the development of the placenta

Question 64

# animal sexual reproduction name the 7 hormones of pregnancy and their purpose

Answer 64

oxytocin - helps the womb to contract during childbirth. HCG - stimulates the corpus luteum to produce progesterone to maintain the pregnancy FSH - responsible for starting follicle (egg) development and causing the level of estrogen, the primary female hormone, to rise LH - drives progesterone production and secretion from the corpus luteum progesterone - thickens uterine lining oestrogen - role in ovulation and thickening lining of uterus relaxin - relax the wall of the uterus by inhibiting contractions, and it also prepares the lining of the uterus for pregnancy

Question 65

# animal sexual reproduction what hormones are responsible for maintaining pregnancy? what 2 hormones are involved in labour

Answer 65

progesterone and oestrogen spike in oestrogen and oxytocin

Question 66

# animal sexual reproduction describe two physiological factors in initiating labour

Answer 66

declining progesterone levels loss of placental competency (deterioration of placenta) high oestrogen levels increasing uterine sensitivity to oxytocin peak in oxytocin physiological state of the foetus (eg release in stress hormones)

Question 67

# animal sexual reproduction name and define each structure of the male reproductive system | 9 parts

Answer 67

testes - male gonads responsible for producing male gametes and secreting testosterone penis - organ used in intercourse to ejaculate semen containing sperm into the female reproductive tract epididymis - coiled tubule where sperm are temporarily stores while they mature scrotum - a double walled pouch that hangs outside the body to regulate the temperature of th etestes for optimal sperm production prostate gland/seminal vesicle- secrete fluid to nourish the sperm and allow the perm to swim vas deferens also known as sperm duct - tubule that carries sperm from the epididymus to the urethra urethra - tube that empties urine from bladder bladder - stores urine

Question 68

# animal sexual reproduction name and define each structure of the female reproductive system

Answer 68

cervix - lower part of the uterus that opens into the vagina ovary - a small oval shaped glandular organ that contains cell that divide to make female gametes (ova) female reproductive hormones are made here ovulation occurs here - the releae of a mature ovum occurs by either ovary once every 28 days uterus - a muscular growth where the fertilised egg implants into the wall and the developing foetus is housed. Growth of the baby occurs here during pregnancy (if fertilisation occurs) fallopian tube - a tube that transports the ovum to the site of fertilisation fertilisation occurs here vagina - a canal with thin muscular walls through which the baby is born if no fertilisation occurs, the lining sheds and menstruation results sperm are introduced into the female body through this structure

Question 69

# animal sexual reproduction create a flow chart, using words and arrows, to list all the organs of the female reproductive system in order from where an egg cell is produced, until it exits the body, either as a baby or in the menstrual flow

Question 70

# animal sexual reproduction what hormone: a) causes an egg to mature in an ovary? b) causes ovaries to secrete oestrogen c) stimulates the development of the lining of the uterus in preparation for pregnancy d) inhibits/blocks the secreasion of FSH and LH e) stimulates the secretion of LH f) causes the ovary to release an egg cell midway through the menstrual cycle g) maintains the lining of the uterus and the placenta during pregnancy h) is responsible for the development of female secondary sexual characteristics such as the development of breasts and growth of pubic hair list your answers in the correct order in which they occur in the reproductive cycle

Answer 70

a) FSH b) FSH

Question 71

# animal sexual reproduction identify the event that triggers the release of progesterone in the ovaries

Answer 71

release of an egg

Question 72

# animal sexual reproduction explain how mestruation is brought about

Answer 72

drop in oestrogen and progesterone levels

Question 73

# plant asexual reproduction describe the circumstances in which asexual reproduction is advantageous to a population

Answer 73

asexual reproduction is an advantage to a group of organisms that are well adapted in a stable environment. Asexual reproduction also allows a popualtion to take advantage of favourable conditions

Question 74

# plant asexual reproduction describe the circumstances in which asexual reproduction is disadvantageous to a population

Answer 74

if an environment undergoes change, asexual organisms are disadvantaged because of their lack of genetic diversity

Question 75

# animal sexual reproduction list the stages of embryonic development and provide a brief description | there are 10

Answer 75

zygote - fertilised egg, 1 cell * the first cell of the new organism, formed by the union of gametes from respective parents * containst he full complement of genetic information Morula - 16 cells * once the zygote divides to form tow cells, it is referred to as the morula. This stage involves cell growth and division until 16 cells are formed. These cells are stem cells

Question 76

# animal sexual reproduction outline cell growth and differentiation during the embryonic development of mammals

Question 77

what are the types of asexual reproduction

Question 78

explain binary fission in bacteria

Question 79

explain binary fission in protists

Question 80

explain budding in protists

Question 81

explain budding in fungi

Question 82

explain spores in fungi