16. Reproduction Flashcards

Question

What are the reproductive organ of the plant?

Answer 1

They usually contain both male and female reproductive parts

Answer 2

Plants produce pollen which contains a nucleus inside that is the male gamete

Answer 3

Unlike the male gamete in humans (sperm), pollen is not capable of locomotion (moving from one place to another)

Answer 4

plants have to have mechanisms in place to transfer pollen from the anther to the stigma This process is known as pollination

Answer 5

here are two main mechanisms by which it occurs: transferred by insects (or other animals like birds) or transferred by wind

Answer 6

YES The structure of insect and wind-pollinated flowers are slightly different as each is adapted for their specific function

Answer 7

protects unopened flower

Answer 8

brightly coloured in insect-pollinated flowers to attract insects

Answer 9

produces and releases the male sex cell (pollen grain)

Answer 10

top of the female part of the flower which collects pollen grains

Answer 11

produces the female sex cell (ovum)

Answer 12

contains the female sex cells (found inside the ovary)

Answer 13

🦟 - large and brightly coloured to attract insects 🌬 - small and dull, often green or brown in colour

Answer 14

🦟- present - entices insect to visit the flower and push past stamen to get to nectar 🌬 - absent - no need to waste energy producing these as no need to attract insects

Answer 15

🦟 - moderate - insects transfer pollen grains efficiently with a high chance of successful pollination 🌬 - large amounts - most pollen grains are not transferred to another flower so the more produced, the better the chance of some successful pollination occurring

Answer 16

🦟 - larger, sticky and / or spiky to attach to insects and be carried away 🌬 - smooth, small and light so they are easily blown by the wind

Answer 17

🦟 - inside flower, stiff and firmly attached to brush against insects 🌬 - outside flower, swinging loose on long filaments to release pollen grains easily

Answer 18

🦟 - inside flower, sticky so pollen grains stick to it when an insect brushes past 🌬 - outside flower, feathery t catch drifting pollen grains

Answer 19

Cross-pollination occurs when the pollen from one plant is transferred to the stigma of another plant of the same species

Answer 20

This is the way most plants carry out pollination as it improves genetic variation

Answer 21

Occasionally, the pollen from a flower can land on its own stigma or on the stigma of another flower on the same plant – this is known as self-pollination

Answer 22

Self-pollination reduces genetic variety of the offspring as all the gametes come from the same parent (and are therefore genetically identical)

Answer 23

Lack of variation in the offspring is a disadvantage if environmental conditions change, as it is less likely that any offspring will have adaptations that suit the new conditions well

Answer 24

On the other hand, cross-pollination relies completely on the presence of pollinators and this can be a problem if those pollinators are missing (eg the reduction in bee numbers is of great importance to humans as bees pollinate a large number of food crops) – this doesn’t apply to wind-pollinated plants

Answer 25

Fertilisation occurs when a pollen nucleus fuses with an ovum nucleus in the ovule

Answer 26

As the pollen has no ‘tail’ to swim to the ovary of a plant, in order to reach the ‘female’ nucleus in the ovary it has to grow a pollen tube

Answer 27

This only happens if the pollen grain has landed on the right kind of stigma (i.e. of the same species as the flower the pollen came from)

Answer 28

The nucleus inside the pollen grain slips down the tube as it grows down the style towards the ovary

Answer 29

The ovary contains one or more ovules which each contain an ovum with a female nucleus that a male pollen nucleus can fuse with

Answer 30

the nuclei (pl) have joined together, that ovule has been fertilised and a zygote has been formed

Answer 31

The zygote will start to divide and eventually form a seed within the ovule

Answer 32

As different plants have different numbers of ovules, this explains why different fruits (which develop from the ovary) have different numbers of seeds (which develop from the ovules)

Answer 33

Germination is the start of growth in the seed

Answer 34

water oxygen warmth

Answer 35

allows the seed to swell up and the enzymes in the embryo to start working so that growth can occur

Answer 36

so that energy can be released for germination

Answer 37

germination improves as temperature rises (up to a maximum) as the reactions which take place are controlled by enzymes

Answer 38

As carbon dioxide is not necessary for germination but also does not inhibit it, it makes no difference whether it is present or not

Answer 39

Set up 4 boiling tubes each containing 10 cress seeds on cotton wool Set each test tube as shown in diagram below Leave tubes in set environment for a period of time: A, B and C incubated at 20°C; D placed in a fridge at 4°C Compare results and see which tube has the greatest number of germinated seeds

Answer 40

NO - needs all 3 factors

Answer 41

produces fluid called semen that provides sperm cells with nutrients

Answer 42

Sperm passes through the sperm duct to be mixed with fluids produced by the glands before being passed into the urethra for ejaculation. Muscular tube that connects testis to urethra.

Answer 43

Tube running down the centre of the penis that can carry out urine or semen. A ring of muscle in the urethra prevents the urine and semen from mixing

Answer 44

Contained in a bag of skin (scrotum) and produces sperm (male gamete) and testosterone

Answer 45

Sac supporting the testes outside the body to ensure sperm are kept at temperature slightly lower than body temperature

Answer 46

Passes urine out of the body from the bladder and allows semen to pass into the vagina of a woman during sexual intercourse

Answer 47

Connects the ovary to the uterus and is lined with ciliated cells to push the released ovum down it. Fertilisation occurs here

Answer 48

Contains follicles in which ova (female gametes) are produced which will mature and develop when hormones are released

Answer 49

Muscular bad with a soft lining where the fertilised egg (zygote) will be implanted to develop into a foetus

Answer 50

Muscular tube that leads to the inside of the woman’s body, where the male’s penis will enter during sexual intercourse and sperm are deposited

Answer 51

The fusion of the nuclei from a male gamete (sperm cell) and a female gamete (egg cell)

Answer 52

They have adaptations to increase the chances of fertilisation and successful development of an embryo

Answer 53

has a flagellum (tail) contains enzymes in the head region (acrosome) contains many mitochondria

Answer 54

Enables it to swim to the egg

Answer 55

To digest through the jelly coat and cell membrane of an egg cell when it meets one

Answer 56

Provide energy from respiration so that the flagellum can move back and forth for locomotion

Answer 57

cytoplasm containing store of energy - jelly like coating that changes after fertilisation

Answer 58

provides energy for the dividing zygote after fertilisation

Answer 59

forms an impenetrable barrier after fertilisation to prevent other sperm nuclei entering the egg cell

Answer 60

SPERM: very small (45nm) EGG: large (0.2mm)

Answer 61

SPERM: Head region and flagellum, many structural adaptations EGG: Round cell with few structural adaptations, covered in a jelly coating

Answer 62

SPERM: Capable of locomotion EGG: not capable of locomotion

Answer 63

SPERM: produced every day in huge numbers (around 100 million per day) EGG: thousands of immature eggs in each ovary, but only released each month

Answer 64

A fertilised egg cell (when nuclei of sperm and egg combine)

Answer 65

Towards the uterus 3 days

Answer 66

Towards the uterus 3 days

Answer 67

It divides several times to form a ball of cells known as an embryo

Answer 68

When the embryo embeds itself in the thick lining of the uterus and continues to grow and develop

Answer 69

the major development of organs

Answer 70

the major development of organs

Answer 71

the embryo gets nutrients from the mother by diffusion through the uterus lining

Answer 72

After this point the organs are all in place, the placenta has formed and the embryo is now called a fetus

Answer 73

The remaining gestation time is used by the fetus to grow bigger in size

Answer 74

The fetus is surrounded by an amniotic sac which contains amniotic fluid

Answer 75

the mother’s blood plasma

Answer 76

The umbilical cord joins the fetus’s blood supply to the placenta for exchange of nutrients and removal of waste products

Answer 77

glucose, amino acids, fats, water and oxygen from the mother’s blood

Answer 78

NO The bloods run opposite each other, never mixing

Answer 79

in the placenta

Answer 80

By the umbilical cord

Answer 81

The mother’s blood also absorbs the waste products from the fetus’s blood in the placenta

Answer 82

carbon dioxide and urea

Answer 83

so that they do not build up to dangerous levels

Answer 84

Movement of all molecules across the placenta occurs by diffusion due to difference in concentration gradients

Answer 85

The placenta is adapted for this diffusion by having a large surface area and a thin wall for efficient diffusion

Answer 86

The placenta acts as a barrier to prevent toxins and pathogens getting into the fetus’s blood

Answer 87

Not all toxin molecules or pathogenic organisms (such as viruses, eg rubella) are stopped from passing through the placenta (this usually depends on the size of the molecule)

Answer 88

Smoke, drink alcohol, do drugs

Answer 89

The umbilical cord is cut and tied off to prevent bleeding. Shrives up and falls off after a few days leaving the belly button

Answer 90

The placenta detaches from the uterus wall shortly after birth and is pushed out due to contractions in the muscular wall of the uterus – known as the afterbirth

Answer 91

Amniotic sac breaks Muscles in the uterus wall contract Cervix dilates (gets wider) Baby passes out through the vagina Umbilical cord is tied and cut Afterbirth is delivered

Answer 92

Amniotic sac breaks Muscles in the uterus wall contract Cervix dilates (gets wider) Baby passes out through the vagina Umbilical cord is tied and cut Afterbirth is delivered

Answer 93

Antenatal (before birth), care is the name given to the care and advice given to expectant mothers along with checks on fetal growth and development

Answer 94

having a balanced diet exercise to stay fit health precautions such as avoiding infections, tobacco, alcohol and other drugs

Answer 95

need to take folic acid to prevent developmental issues with the fetus

Answer 96

Enlarge and become prepared to secrete milk

Answer 97

sucking action of the baby at the breast

Answer 98

contains exactly the right nutrients in the right amounts the baby needs at different stages contains antibodies which help the baby prevent infection helps develop a bond between mother and baby is free

Answer 99

if it does not come easily to the mother it can contribute to postnatal depression responsibility for feeding the baby is solely with the mother

Answer 100

allows the father to bond with the baby - allows the mother more freedom as she is not solely responsible for feeding the baby

Answer 101

risk of infections increased if bottles and equipment are not properly sterilised is expensive

Answer 102

A fluid-filled sac that protects the embryo from damage and unequal pressures from acting upon it.

Answer 103

Birth control methods are important in keeping family sizes small and in limiting the increase in the human population

Answer 104

Humans can use mechanical, chemical, surgical and natural contraceptive methods to prevent a pregnancy

Answer 105

Some birth control methods also give protection from sexually transmitted infections

Answer 106

avoiding sexual intercourse completely

Answer 107

avoiding sexual intercourse during the fertile period of the menstrual cycle when ovulation occurs

Answer 108

the exact time ovulation happens can be worked out by monitoring body temperature and quality of cervical mucus

Answer 109

No, it’s the least reliable method

Answer 110

IUD/IUS Contraceptive pill, implant, injection

Answer 111

an intrauterine device or intrauterine system

Answer 112

a small device fitted inside the uterus by a doctor or nurse

Answer 113

it releases sex hormones which thicken the mucus produced in the cervix, making it difficult for sperm to swim into the uterus it also thins the lining of the uterus, making it more difficult for a fertilised egg to implant

Answer 114

an IUD also interferes with the passage of sperm through the uterus, in which way it is acting as a barrier method of birth control

Answer 115

may contain just progesterone or a mixture of progesterone and oestrogen

Answer 116

Yes, very when taken regularly

Answer 117

both last several months - increase the effectiveness as they remove the risk of forgetting to take a pill regularly

Answer 118

Condom Femidom Diaphragm

Answer 119

All work by preventing sperm from reaching the egg

Answer 120

latex sheath worn over the penis

Answer 121

prevents sperm entering the vagina as ejaculate remains in condom

Answer 122

Protects against STI’s

Answer 123

latex sheath inserted into the vagina

Answer 124

a rubber cap that fits over the entrance to the cervix

Answer 125

prevents entry of sperm into the uterus

Answer 126

often used with a spermicide (cream which kills sperm)

Answer 127

vasectomy - female sterilisation (tubal ligation)

Answer 128

the sperm ducts are cut, meaning that no sperm is present in the semen when ejaculation occurs

Answer 129

the oviducts are cut or tied off, preventing eggs from reaching the uterus or sperm from reaching the eggs

Answer 130

very effective but difficult to reverse

Answer 131

They work by mimicking some of the hormone levels during pregnancy By raising the levels of progesterone and oestrogen, the uterus lining is maintained and development of another egg cell is prevented This means that sex at any time of the month cannot cause pregnancy as no egg is released to be fertilised

Answer 132

In situations where couples find it difficult to conceive, fertility treatments can improve their chances

Answer 133

Artificial Insemination Fertility Drugs In Vitro Fertilisation (IVF)

Answer 134

If the male is not producing healthy sperm

Answer 135

donor sperm is used - The sperm are placed into the female’s vagina at the fertile point in her menstrual cycle

Answer 136

The male must be able to cope with the fact that the child is not biologically his Sperm donors may father multiple children who are not able to know their parentage

Answer 137

This method is used when the female is not producing enough eggs

Answer 138

Hormones, including FSH, are given to her to stimulate egg production

Answer 139

Several eggs can be released at once so this increases the chance of multiple births (twins or triplets etc)

Answer 140

If the female cannot conceive naturally even after taking fertility drugs, or if there are issues with both male and female fertility in a couple, IVF can be used

Answer 141

This involves fertility drugs being given to the female to stimulate egg production before they are harvested from the ovary The eggs are then inseminated in a petri dish using sperm from the male Once embryos have formed, they are placed back into the uterus of the female Several embryos are implanted to increase the chance of one developing further

Answer 142

IVF is relatively expensive and not all couples can afford it As several embryos are implanted, the risk of multiple births is quite high Some women use IVF to get pregnant at a later age than they would be able to conceive naturally

Answer 143

Unprotected sexual intercourse can lead to the transfer of pathogens via exchange of body fluids

Answer 144

HIV (Human Immunodeficiency Virus), the virus that usually leads to the development of acquired immunodeficiency disease (AIDS)

Answer 145

HIV can also be spread via: sharing needles with an infected person, blood transfusions with infected blood from mother to fetus through the placenta mother to baby via breastfeeding

Answer 146

people often suffer mild flu-like symptoms

Answer 147

These symptoms pass and for a period of time infected people might not know they are infected

Answer 148

The virus infects a certain type of lymphocyte of the body’s immune system

Answer 149

Normally lymphocytes seek out and destroy pathogens that enter the body, producing antibodies that attach to pathogens, enhancing phagocytic activity

Answer 150

HIV avoids being recognised and destroyed by lymphocytes by repeatedly changing its protein coat

Answer 151

It then infects a certain type of lymphocyte and uses the cells’ machinery to multiply

Answer 152

This reduces the number of lymphocytes of the immune system, and also the number of antibodies that can be made

Answer 153

It decreases the body’s ability to fight off infections, eventually leading to AIDS (Acquired immunodeficiency)

Answer 154

HIV attaches to receptors on lymphocyte

Answer 155

HIV injects its genetic material into the lymphocyte, which becomes a HOST CELL

Answer 156

After making many copies of itself, the host cell is destroyed by HIV

Answer 157

Limiting the number of sexual partners an individual has Not having unprotected sex, but making sure to always use a condom Getting tested if unprotected sex or sex with multiple partners has occurred Raising awareness by education programmes

Answer 158

Primary sexual characteristics are present during development in the uterus and are the differences in reproductive organs etc between males and females

Answer 159

Secondary sexual characteristics are the changes that occur during puberty as children become adolescents

Answer 160

They are controlled by the release of hormones – oestrogen in girls and testosterone in boys

Answer 161

breasts develop body hair grows menstrual cycle begins hips get wider

Answer 162

growth of penis and testes growth of facial and body hair muscles develop voice breaks testes start to produce sperm

Answer 163

growth of sexual organs and growth of body hair

Answer 164

Emotional changes also occur due to the increased levels of hormones in the body These include more interest in sex and increased mood swings

Answer 165

Starts in early adolescence in girls (around age 12) and is controlled by hormones

Answer 166

The average menstrual cycle is 28 days long

Answer 167

Ovulation (the release of an egg) occurs about halfway through the cycle (day 14) and the egg then travels down the oviduct to the uterus

Answer 168

Failure to fertilise the egg causes menstruation (commonly called a period) to occur – this is caused by the breakdown of the thickened lining of the uterus

Answer 169

Menstruation lasts around 5 – 7 days and signals the beginning of the next cycle

Answer 170

After menstruation finishes, the lining of the uterus starts to thicken again in preparation for possible implantation in the next cycle

Answer 171

The menstrual cycle is controlled by hormones released from the ovary and the pituitary gland in the brain

Answer 172

Oestrogen levels rise from day 1 to peak just before day 14

Answer 173

stimulates the uterus to develop a lining (to replace lining lost during menstruation) post-ovulation, inhibits FSH and LH production in the pituitary gland causes the egg to mature

Answer 174

The peak in oestrogen occurs just before the egg is released

Answer 175

Progesterone stays low from day 1 – 14 and starts to rise once ovulation has occurred

Answer 176

The increasing levels cause the uterine lining to thicken further a fall in progesterone levels causes the uterine lining to break down (menstruation / ‘period’) - maintains lining of uterus - inhibits FSH and LH production

Answer 177

the pituitary gland

Answer 178

stimulates egg maturation in the follicles of the ovary - stimulates follicles in the ovaries to secrete oestrogen

Answer 179

The pituitary gland is stimulated to release luteinising hormone (LH) when oestrogen levels have reached their peak

Answer 180

stimulates ovulation (release of egg into oviduct) - stimulates ovary to produce progesterone (ovulation results in the formation of a corpus luteum which secretes p)

Answer 181

If pregnancy does occur the corpus luteum continues to produce progesterone, preventing the uterus lining from breaking down and aborting the pregnancy

Answer 182

It does this until the placenta has developed, at which point it starts secreting progesterone and continues to do so throughout the pregnancy

Answer 183

Sexual reproduction is a process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other.

Answer 184

Fertilization is the fusion of the nuclei from a male gamete (sperm) and a female gamete (egg cell).

Answer 185

The nuclei of gametes are haploid and the nucleus of a zygote are diploid.

Answer 186

Produces testosterone. Manufactures the male gametes. Delivers them to the site of fertilization.

Answer 187

Made up of many coiled tubes which produce the male gametes (sperm). The cells between the tubes produce testosterone.

Answer 188

Sac of skin that encloses the testes and hang outside of the body between the legs where the testes are protected. Temperature is 2 - 3°C lower than the body temperature - ideal for sperm development.

Answer 189

Carries sperm from the testis to the urethra.

Answer 190

Produces fluid which makes up most of the sperm.

Answer 191

Carries semen from the sperm duct to the tip of the penis. Carries urine, a valve prevents this happening at the same time.

Answer 192

Erectile tissue can be stiffened by filling with blood. Once erect can be used to deliver sperm to the vagina of the female (ejaculation).

Answer 193

Produces oestrogen/progesterone. Develops female gametes. Accepts sperm. Allows development/birth of the fetus.

Answer 194

Contains thousands of follicles which develop the ova (eggs) and produce oestrogen and progesterone.

Answer 195

Carries the ovum to the uterus. (Fertilization usually occurs in the first third of the oviduct).

Answer 196

Site of implantation and development of the fetus.

Answer 197

Ring of muscle at the lower end of the uterus.

Answer 198

Receives the penis during intercourse, sperm are deposited here. Baby passes down the vagina during birth.

Answer 199

Egg cells and sperm cells are made by meiosis.

Answer 200

Flagellum is a tail used for swimming.

Answer 201

Middle piece containing mitochondria to release energy so the sperm can swim.

Answer 202

The acrosome is a vesicle containing enzymes to dissolve through the jelly surrounding the egg cell.

Answer 203

Cytoplasm contains a store of energy that provides energy for cell division after fertilization.

Answer 204

Jelly coat changes after fertilization to form an impenetrable barrier to prevent other sperm nuclei entering the egg cell.

Answer 205

Sperm cell = Small, very little food store. Egg cell = Much larger than sperm cell as it contains a food store in the cytoplasm

Answer 206

Sperm cell = Contains a lot of mitochondria to release energy so the sperm can swim using tail movement. Egg cell = Does not move itself (is moved along the oviduct by cilia and peristalsis.

Answer 207

Sperm cell = Flagellum, Mitochondria, and enzymes in the acrosome. Egg cell = Energy stores in the cytoplasm, jelly coat that changes at fertilization so only one sperm cell enters and fertilizes.

Answer 208

23 which is the haploid number.

Answer 209

Sperm cell = (100 000 000) many per day from puberty to old age. Egg cell = One a month from alternate ovaries from puberty to middle age (menopause), except when pregnant or taking the contraceptive pill.

Answer 210

During sexual intercourse, the penis becomes erect and enters the vagina. Sperm are released from the testes and travel by peristalsis along the sperm ducts. Contractions of the urethra move the seminal fluid through the penis into the vagina.

Answer 211

The zygote forms an embryo which is a ball of cells that implants into the lining of the uterus.

Answer 212

Enzymes released by the acrosome break down the jelly coat so that the nucleus of the sperm can fertilize the nucleus of the egg cell. The ovum membrane alters to form a barrier to the entry of other sperm. The new cell contains a set of genetic material from the mother and a set from the father. It is a diploid zygote with 46 chromosomes. The fertilized ovum or zygote now starts to divide by mitosis and continues to move down the oviduct by peristalsis of the oviduct muscles and the beating of cilia to the uterus where it implants in the thickened uterus lining. Once the embryo is attached to the lining of the uterus, some of its outer cells combine with some of the mother’s cells and a placenta begins to develop.

Answer 213

exchange of dissolved nutrients e.g. glucose, amino acids, and excretory products e.g. urea. Exchange of dissolved gases by diffusion e.g.oxygen and carbon dioxide. Antibodies diffuse from the mother to the baby to provide passive immunity. Protection of the fetus from the mother’s immune system. - there is no direct contact between maternal and fetal blood. The mother’s blood flows under high pressure and would damage the delicate blood vessels of the fetus also if the mother and fetus have different blood groups then the mother’s antibodies and platelets may cause it to clot. It provides a barrier to toxins and pathogens however some toxins e.g. nicotine, alcohol, heroin, and pathogens can diffuse across the placenta and affect the fetus. Secretion of hormones (progesterone) which maintains the lining of the uterus during pregnancy as the corpus luteum breaks down.

Answer 214

The umbilical cord connects the fetus to the placenta.

Answer 215

The cord contains the umbilical artery which carries deoxygenated blood and wastes (e.g. carbon dioxide and urea) from the fetus to the placenta and the umbilical vein which carries oxygenated blood and nutrients(e.g. glucose and amino acids) from the placenta to the fetus.

Answer 216

mechanical shock. drying out. temperature fluctuations.

Answer 217

Throughout pregnancy the fetus is surrounded by a membrane called the amniotic sac which contains amniotic fluid.

Answer 218

Facial hair develops. Chest broadens. Voice deepens. Hair develops on chest, under armpits and in pubic region. Penis and testes become larger. Sperm production begins.

Answer 219

Breasts develop. Hips broaden. Hair grows under armpits and in the pubic region. Vagina enlarges. Oestrogen begins the cycle of egg production and prepares the uterus lining for implantation.

Answer 220

At puberty, a person becomes physically able to reproduce. At puberty the brain instructs the pituitary gland to make hormones (Follicle Stimilauting Horomore and Luteinizing Hormone) that stimulate the primary sex organs to release the sex hormones into the blood stream. The testes release testosterone and the ovaries release oestrogen. These hormones only affect the target organs which have receptors to recognise them.

Answer 221

Prepare the uterus to receive any fertilised ova. Control the development of mature ova.

Answer 222

The cycle of producing and releasing mature ova is called the menstrual cycle.

Answer 223

Girls are born with thousands of potential egg cells in their ovaries. Each potential egg is surrounded by a small group of cells and together they form a follicle (Follicle Stimulating Hormone). Ovaries do not produces any more eggs in their life time. At puberty (between 10 and 15 years) some of the follicles start to develop and girls start to have periods.

Answer 224

Sexually transmitted infection is an infection that is transmitted through sexual contact.

Answer 225

Human immunodeficiency virus (HIV) is a pathogen that causes AIDS (and STI).

Answer 226

in blood through transfusions, hypodermic needles, and mixing of blood. in semen during unprotected sexual intercourse with an infected person. across the placenta during pregnancy. during birth when the mother and baby’s blood streams come in close contact. during breast feeding through breast milk.

Answer 227

in blood through transfusions, hypodermic needles, and mixing of blood. in semen during unprotected sexual intercourse with an infected person. across the placenta during pregnancy. during birth when the mother and baby’s blood streams come in close contact. during breast feeding through breast milk.

Answer 228

By using condoms, drug users must not share needles, screen blood for transfusions.

Answer 229

Anti-retroviral drugs can be given along with counseling. There is NO cure.

Answer 230

There are none for HIV. After 8 - 10 years it will develop into Acquired immunodeficiency syndrome (AIDS).

Answer 231

AIDS is a collection of diseases which result from the weakening of the immune system.

Answer 232

Symptoms include flu symptoms, swollen glands, high temperature.

Answer 233

Aids cannot be cured as it is from the Human immunodeficiency virus, so death will result.

Answer 234

Repairs uterus lining. Inhibits Follicle Stimulating Hormone. Stimulates Luteinising Hormone release. Stimulates development of female sexual characteristic.

Answer 235

Stimulates release of mature ovum. Development of the corpus luteum.

Answer 236

Thickens uterus lining. Inhibits Follicle Stimulating Hormone. Prevents Menstruation. Prevents production of more eggs.

Answer 237

Menstruation = Day 0 - Day 5. Repair Phase = Day 6 - Day 12. Ovulation = Day 13 - Day 15. Receptive Phase = Day 16 - Day 21. Premenstrual Phase = Day 22 - Day 28.

Answer 238

Stimulate follicle growth to secrete oestrogen and develop the ovum.

Answer 239

If fertilization does take place progesterone levels remain high and the uterus lining is maintained.

Answer 240

If fertilization does not take place the progesterone levels decrease and menstruation takes place.

Answer 241

A process resulting in the production of genetically identical offspring from one parent

Answer 242

Population can be increased rapidly Can exploit suitable environments quickly Time and energy efficient Reproduction is completed much faster than sexual reproduction

Answer 243

limited genetic variation in population population is vulnerable to changes in conditions and may only be suited for one habitat Disease is likely to affect the whole population as there is no genetic variation

Answer 244

As it means that a plant that has good characteristics can be made to reproduce asexually and the entire crop will show the same characteristics

Answer 245

A process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other

Answer 246

Increases genetic variation Species can adapt to new environment due to variation Disease is less likely to affect population due to variation

Answer 247

Takes time and energy to find males | Difficult for isolated members of the species to reproduce

Answer 248

The fusion of gamete nuclei

Answer 249

Protects unopened flower

Answer 250

Brightly coloured to attract insects

Answer 251

produces and releases the male sex cell

Answer 252

top of the female part that collects pollen grains

Answer 253

produces the female sex cell

Answer 254

contains the female sex cell

Answer 255

large and brightly coloured to attract insects

Answer 256

entices insects to visit the flower and push past stamen to get to nectar

Answer 257

large sticky spiky to attach to insects

Answer 258

inside flower stiff to brush against insects

Answer 259

inside flower sticky so pollen grains stick to it when an insect brushes past

Answer 260

small, dull

Answer 261

no need to waste energy producing those

Answer 262

Large amounts most pollen are not transferred to another flower.

Answer 263

outside flower swinging loose on long filaments to release pollen grains easily

Answer 264

Outside to catch drifting pollen grains

Answer 265

When it lands the stigma inside the flower brush against the insect. It is sticky so the pollen sticks to it. A pollen tube then grows down the style towards the ovary and enters the ovary via the micropyle (small hole in ovary) at this point fertilisation occurs and the ovule developed into a seed which developed into a fruit. (Ovule wall becomes seed coat)

Answer 266

The first root

Answer 267

The first shoot

Answer 268

The first leaf and food store

Answer 269

It covers and protects the embryo before germination (seed coat)

Answer 270

The period of time between fertilisation and germination

Answer 271

The process by which a seed changes into a plant. Root, shoot appears the seed cost splits.

Answer 272

Water is needed in order to burst that tests and allows the radicle and plumule to develop. It also allows metabolic reactions to happen as it activates enzymes

Answer 273

Oxygen is needed for aerobic respiration to happen

Answer 274

A warm temperature not only lets the seed know when it should germinate but it also lets rapid enzyme reactions to happen.

Answer 275

The 1st cell after fertilisation when the diploid number has been restored.

Answer 276

The stamen is made up of the anther and the filament (which holds up the anther) They are the long stick things inside the flower. They produce pollen grains which stick or hook onto the insects. The anther and filament are firm and stiff to brush against the insects.

Answer 277

The stigma is also inside the flower and the stamen are on top of it. It is sticky so pollen grains stick onto it when an insect brushed past.

Answer 278

They are large and brightly coloured to attract insects

Answer 279

They have sweet, sugary nectar which attracts insects.

Answer 280

The stamen is outside the flower and the anthers are loose on long filaments so pollen grains are released easily, the grains are smooth and lights so can be carried by the wind and not clump together

Answer 281

It is outside and feathery to catch drifting pollen grains

Answer 282

They are small and usually green or brown.

Answer 283

The transfer of pollen from the anther to the stigma then ovule to allow fertilisation to take place.

Answer 284

A pollen tube is grown down the style and into the ovary, the nucleus of the pollen grains passes down the tube to fertilise the egg cell in the ovule (fertilisation). The embryo developed and the ovary forms the fruit and the ovules become seeds.

Answer 285

The process where a plant grows from a seed.

Answer 286

They use up their food stores until they can photosynthesise

Answer 287

Also known as a sex cell. A female and male gamete undergo fertilisation to become a zygote. In a plant the female gamete is the egg and the male gamete is the pollen.

Answer 288

They produce a clone. Some plants have lateral buds on the outside which grows another plant others have side branches with plantlets on them (spider plant) and others produce runners which extend and grow a plant from that (e.g. Strawberry plants) this can be done artificially through tissue culture and taking cuttings

Answer 289

Is protects the plant whilst letting the sun shine in as it is thin and transparent

Answer 290

A layer of palisade cells which absorb light. They are near the surface so light can get to them easily and palisade cells are filled with chloroplasts

Answer 291

It is made from dead cells and lignin. It moves water through the plant from the roots to the leaves via the stem.

Answer 292

It is made from living cells and moves dissolved sugars from photosynthesis and other soluble food molecules from the leaves to growing and storing tissues

Answer 293

It is filled with air spaces to allow CO2 to diffuse from the stomata tot he photosynthesising cells. It provides a large internal sa:v

Answer 294

The lower epidermis is at the bottom of the leaf. It contains guard cells that open and close the stomata where gas exchange happens, water vapour is also lost through the stomata during transpiration

Answer 295

A thin waxy protective layer on top of the leaf. It reduces water loss by evaporation and prevents entry of pathogens

Answer 296

First day the lining of the uterus is shed and then FHS is released from the pituitary gland stimulating the growth of a new egg cell surrounded by a cluster of cells called a follicle

Answer 297

The follicle cells produce oestrogen which causes the lining of the uterus to build up again. Around day 14 ovulation happens (where a mature egg is released) and LH is released.

Answer 298

FSH is released from the pituitary gland and causes an egg to mature in an ovary and stimulates the ovaries to release oestrogen

Answer 299

Released from the ovaries and it stops FSH being produced (so that only one egg matures in a cycle). Repairs and thickens the uterus lining. Stimulates the pituitary gland to release LH.

Answer 300

It is released from the pituitary gland and triggers ovulation (the release of a mature egg)

Answer 301

It is released from the ovaries and it maintains the lining of the uterus during the middle part of the menstrual cycle and during pregnancy.

Answer 302

The egg travels down the oviduct and is shed with the uterus. (The egg travels down the oviduct for 14 days and the oestrogen and progesterone levels fall in the last 2 days)

Answer 303

A When the embryo embeds itself into the uterus lining

Answer 304

It acts as a ‘shock absorber’ to protect it from bumps to the mothers body and provides a stable environment by regulating temperature

Answer 305

The intervillous space

Answer 306

It can help stop harmful pathogens and some viruses from getting into the babies blood stream

Answer 307

To the baby: small soluble nutrients (glucose, other sugars, amino acids, fatty acids and glycerol) and oxygen (as it can not do gas exchange by itself) antibodies are also transferred across (as they are very small) to provide immunity To the mother: carbon dioxide and urea

Answer 308

The lining is folded and has villi to increase surface area. It also has a big blood supply.

Answer 309

Veins and arteries

Answer 310

the tube inside the penis that can carry urine or semen. A ring of muscle ensures that urine and semen do not get mixed up.

Answer 311

The sperm pass through the sperm ducts, and mix with fluids produced by glands. The fluids provide the sperm cells with nutrients. The mixture is semen

Answer 312

To produce sperm To make the hormone testosterone

Answer 313

Ova (eggs) ovum (egg)

Answer 314

Each ovary is connected to the uterus by an oviduct (fallopian tube). The oviduct is lined with ciliated cells. Every month, an ovum (egg) develops and becomes mature, and is released from an ovary. The cilia waft the ovum along inside the oviduct and into the uterus.

Answer 315

The uterus is a muscular bag with a soft lining. It is where a baby develops until its birth. The cervix is a ring of muscle at the lower end of the uterus. It keeps the baby in place while the woman is pregnant.

Answer 316

The vagina is a muscular tube that leads from the cervix to the outside of the woman’s body. The opening to the vagina has folds of skin called labia that meet to form a vulva. The urethra also opens into the vulva, but it is separate from the vagina. It passes urine out of the body from the bladder.

Answer 317

to pass urine out of the body from the bladder - to pass semen into a woman

Answer 318

to pass urine out of the body from the bladder - to pass semen into a woman

Answer 319

process resulting in the production of genetically identical offspring from one parent

Answer 320

process resulting in the production of genetically identical offspring from one parent

Answer 321

the process involving the fusion of the nuclei of two games (sex cells) to form zygote and the production of offspring that are genetically different from each other.

Answer 322

the fusion of two gamete nuclei

Answer 323

transfer of pollen grains from the anther to the stigma of the flower or flowers

Answer 324

the transfer of pollen grains from the anther of a flower to the stigma of the same flower or different follower on the same plant

Answer 325

transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species

Answer 326

the infection that is transmitted via body fluids through sexual contact

Answer 327

to make sure a species can continue its generation

Answer 328

organisms do not need to find a partner and this saves time and energy offsprings are genetically identical to their parents, none of the offsprings will be less well adapted to the environment organisms reproduce even in isolation and prevent extinction in the wild the single organism can develop a colony hence very useful in crop production

Answer 329

does not lead to genetic variation in a population the species may only be suited to one habitat spreading diseases or change in the environment may affect all the individuals in a population which may lead to the extinction of species population can be difficult to control in the wild which increases the competition among the species for survival -negative mutation live longer in asexual organisms, diseases can be inherited from the parent

Answer 330

produces genetic variation in the offspring. the species can adapt to new environments due to variation, which gives them a survival advantage and prevent the extinction a disease is less likely to affect all the inviduals in a population

Answer 331

produces genetic variation in the offspring. the species can adapt to new environments due to variation, which gives them a survival advantage and prevent the extinction a disease is less likely to affect all the individuals in a population

Answer 332

time and energy are needed to find a mate not possible for an isolated inviduals to reproduce

Answer 333

sexual reproduction: - 2 parents - Cells divide by meiosis - Variation and diversity asexual reproduction: - 1 parent - Cells divide by fission or budding - Little variation

Answer 334

Both processes are types of reproduction and both produce offspring

Answer 335

Both processes are types of reproduction and both produce offspring

Answer 336

yeast budding binary fission

Answer 337

the process by which a new, duplicate plant or animal begins to form at the side of the parent and enlarges until an individual is formed - very common in plants and some animals - example: cactus and hydra - budding is very common in yeast - in budding, an outgrowth (bud)develops from the body water. the bud grows to form a daughter organism which detaches to become independent. cytoplasm divides unequally

Answer 338

type of cell division in unicellular organisms which produces two organisms after the complete division of the cells. binary fission is common in bacteria. in binary fission, a single-cell bacterium divides into two identical daughter bacteria. bacteria reproduce by this method where all conditions such as availability of nutrients, temperature, and moisture are available

Answer 339

cell elongation replication of DNA, forming 2 identical DNA strands. the newly formed strands of DNA move to the opposite poles of the cells. in the middle of the cell, a construction appears which deepens progressively. cell divides into two equal halves, followed by the formation of a cross wall to form 2 independent daughter cells

Answer 340

in this form, the body of the parent breaks down into distinct pieces, each of which can produce offspring. example: pieces of coral broken off in storms can grow into new colonies, a new starfish can grow from one detached arm, and some plants can grow from cutting them up and replanting them( tissue culture is also a method to reproduce some plants)

Answer 341

green plants are quite sophisticated in their methods of asexual reproduction. offspring may be produced by rynners, blubls , rhizomes or tubes

Answer 342

potato plant

Answer 343

onions, garlic

Answer 344

strawberry

Answer 345

anther filament

Answer 346

stigma, style, ovule, ovary

Answer 347

1) calyx 2)corrola 3) stamen 4) carpel

Answer 348

many petals

Answer 349

more than 1 speal

Answer 350

the colorful part of the flower. attracts insects in insect-pollinated plants

Answer 351

male part of the plant. makes pollen

Answer 352

joins the anther to the rest of the flower and provides angle for pollination

Answer 353

female part of the plant. recieves pollen

Answer 354

contains the ovules

Answer 355

contains female gametes

Answer 356

contains male gametes

Answer 357

makes nectar to attract insects in insect pollinated plants

Answer 358

makes nectar to attract insects in insect pollinated plants

Answer 359

stamen consists of 2 parts, an anther and a filament anther is where meiosis occurs to produce haploid pollen if filament is a stalk that supports the anther and provides an angle for pollination

Answer 360

carpel consists of stigma, style, ovary, and ovule - sticky stigma receives pollen and also provides nutrition - pollen grows a tube down the style - meiosis occurs in the ovary to produce a haploid nucleus

Answer 361

carpel consists of stigma, style, ovary, and ovule - sticky stigma receives pollen and also provides nutrition - pollen grows a tube down the style - meiosis occurs in the ovary to produce a haploid nucleus

Answer 362

pollination mechanism

Answer 363

when pollination occurs with the help of wind

Answer 364

when pollination occurs with the help of insects or other pollinators

Answer 365

very few pollen grains can pollinate the flower -purity of the race is maintained self-pollination avoids wastage of pollen grains less chance of failure of pollination

Answer 366

no variations occur if a plant gets hit by a disease. there is no possibility of survival and population decreases it does not result in the creation of new species, a lower rate of evolution continuous self-pollination results in weak progenies

Answer 367

the offspring are healthier due to variation the seeds produced in large numbers are more visible the seeds develop and germinate properly and grow into proper plants results in genetic variation because cross-pollinated can be carried out between two different varieties of the same species

Answer 368

in insect-pollinated flowers, produced pollen grains that are smaller and lighter in weight, which can be carried in wind easily. in insect-pollinated flowers, they produced pollen grains that are larger in size, stick and spiny which helps to carry the pollen grain

Answer 369

sepal + petal

Answer 370

after pollen lands on the stigma. a pollen tube grows down the style to the ovary the generative cells create the 2 sperm nuclei ( mitosis) double fertilization occurs( one sperm fertilizes) the egg one sperm fertilizes the 2 polar nuclei together( central cell)

Answer 371

provide nutrition for growing embryos and in human population

Answer 372

the sperm nucleus and egg nucleus joined to form a diploid embryo the other sperm nucleus and the two polar nuclei to form a triploid endosperm. the endosperm is the nutrients supply for energy

Answer 373

large, brightly colored petals to attract insects often sweetly scented to attract insects moderate quantity of pollen- less wastage than wind pollination -pollen is often sticky or spiky to stick to insects anthers firm and inside to brush against insects stigma inside the flower so that the insect brushes it stigma has a sticky coating, pollen sticks to it

Answer 374

small petals, often brown or dull green- no need to attract insects no scent: no need to attract insects -no nectar: no need to attract insects -pollen produced in great quantities because it does not reach another flower pollen is very light and smooth: so it can be blown in the wind and stops it from clumping together -anther loosely attached and dangle out to release pollen into the wind stigma hangs outside the flower to catch the drifting pollen stigma feathery or net-like to catch the drifting pollen

Answer 375

sex organs

Answer 376

sex organs

Answer 377

egg ( ova )

Answer 378

fertilized egg

Answer 379

1) scortum 2) testicles 3) testosterone 4) sperm 5) prostate gland 6)urethra 7) epididymis

Answer 380

pouch-like sac holding both testicles in a separate compartment that hangs underneath the penis. maintains temperature for spermatogenesis

Answer 381

2 glands in the male, located in the scrotum , which produce male hormones(testosterone)

Answer 382

the male reproductive hormone made by the testicles which causes a change in puberty

Answer 383

process in which sperm cells are produced

Answer 384

the microscopic cells produced by the male testicles which can fertilize the female ovum

Answer 385

man’s gland that helps make a sewer which is highly alkaline

Answer 386

a tube that connects with the vas differentia to carry sperm cells out of the body

Answer 387

the structure that forms a mass over the back and upper part of each testis, stores sperm cells for further maturity

Answer 388

sperms move by the process of peristalsis

Answer 389

1)vagina 2) cervix 3) uterus 4) oviduct ( fallopian tubes) 5) ovaries

Answer 390

passageway between the uterus and the outside of a woman’s body which receives the sperm cells. the site where sperm cells get fully matured

Answer 391

opening from the uterus to the vagina. It produces mucus which provides nutrients for the sperm and is alkaline in nature

Answer 392

the place where the fetus grows and develops in a woman’s abdomen

Answer 393

2 tubular structures reading from the ovaries to the uterus. site where fertilization takes place

Answer 394

organs holding a woman’s egg. which produces the female hormone estrogen and progesterone

Answer 395

sperm cells are specialized in a number of ways. the head contains a haploid nucleus. they have a flagellum ( tail) which moves by energy generated by many mitochondria and propels the cells. the head of the cell contains an acrosome, which secretes acrosomal enzymes to break the cell membranes during fertilization.

Answer 396

An egg cell has adapted to its function through the presence of cytoplasm, which increases its surface area to store nutrients. it has a maximum number of mitochondria. it is surrounded by a jelly coat ( zona pellucida) which maintains the entry of only one sperm head. also protects the embryo in the early stages

Answer 397

both sperm and egg cells have haploid nuclei. both sperm and egg cells have a large number of mitochondria. sperm cells are very small in comparison to large egg cells. sperms are produced in large numbers as one or two eggs are produced in each cycle. sperm cells are motile whereas egg cells are non-motile. sperm cells have acrosome which is absent in egg cells. sperm cells have a tail to swim which is absent in egg cells. sperm cells have either “x” or “y” chromosomes whereas egg cells have only ‘x’ chromosomes. the jelly coat is absent in sperm cells and present in egg cells. egg cells have stored nutrients which is absent in sperm cell

Answer 398

the sperm swim through the cervix across the uterus and enters the oviduct. the sperm may be stuck to the surface. the acrosome at the head of the sperm secretes enzymes that digest the part of the cell membrane of sperm as well as an egg cell. the jelly coat becomes hard to prevent the entry of other sperms. then the male nucleus fuses with the female nucleus termed as fertilization. the fertilized egg becomes the zygote which starts to divide by mitosis to form an embryo which is a cluster of cells that implants into the wall of the uterus , a process termed implantation

Answer 399

1) protects the fetus from functional injuries 2) prevents the entry of pathogens 3) absorbs the metabolic wastes of the developing fetus 4) produces amniotic fluid amniotic fluid accomplishes numerous functions for the fetus include: - protection from outside injury by cushioning sudden blows or movements - allows frictionless fetal movement and permits symetrical musculoskeletal development - maintaining a relatively constant temperature for the environment surrounding the fetus. thus protecting the fetus from heat loss - maintains the osmotic balance in developing fetus

Answer 400

the placenta is a temporary organ formed during the pregnancy form of the embryo during implantation in the endometrium. placenta develops an amniotic sac to protect the fetus placenta secretes progesterone hormone to keep endometrium intact and strong during pregnancy placenta never allows the mixing of maternal and fetal blood -placenta helps in the gaseous exchange of the developing fetus through the diffusion process placenta provides nutrition for the fetus placenta removes metabolic wastes and excretory products from the fetus

Answer 401

primarily it serves as an oxygen source for the fetus, this is especially important because the fetus is unable to breathe having neither functional lungs nor an oxygen source and the cord provides the fetus the oxygen it needs to live the umbilical cord also serves as a source of nutrients. including carbohydrates, proteins, fasts as well as vitamins and minerals along with antibodies for passive immunity finally the umbilical cord transfers metabolic waste products and deoxygenated blood away from the fetus near the maternal circulation where the exchange of gases and removal of excretory products take place.

Answer 402

1) growth and development of facial hair, armpit, and pubic hair 2) a deepening of the voice 3) broadening of shoulders 4) muscles become stronger: sperm produced in adult amounts, throughout lude, if good health is present, there is validity to be a father

Answer 403

1) growth and development of armpit and pubic hair 2) widening of the hip bone ( pelvic bone) 3) growth and development of memory glands 4) start of the menstrual cycle- monarch age 45-55 menopause ( cycle stops, cannot be a mother again)

Answer 404

the hormone responsible for the secondary sexual characteristics of the female controls the menstrual cycle, responsible for the growth and development of the endocardium. produced by the ovaries

Answer 405

the hormone produced by the yellow bodies which help the lining of the uterus( endometrium) strong and intact during pregnancy

Answer 406

a substance that brings to life a few of the ovum in one of the ovaries. it is secreted by the pituitary gland in the brain

Answer 407

causes the follicle to burst, and allows the ovum to fall into the opening of the fallopian tube- ovulation. it is also secreted by the pituitary gland

Answer 408

when egg is released from the ovary

Answer 409

sexually transmitted infections in an infection that is transmitted via body fluids through sexual contact human immunodeficiency virus( HIV) is an example of STI, STD and aids

Answer 410

human immunodeficiency virus

Answer 411

acquired immunodeficiency syndrome

Answer 412

sexually transmitted disease

Answer 413

transmitted in the blood and semen unprotected sexual activities blood transfusion sharing drug needles and syringes

Answer 414

destroying the lymphocytes develop other communicable diseases, the immune system can not produce antibodies developement of cancer cells, slow function of the brain

Answer 415

illness and problems for you by attaching your immune system When this happens, other diseases and conditions may occur because of your weakend immune system or because of the long-term effect of HIV on your body which is AIDS

Answer 416

process resulting in the production of genetically identical offspring from one parent

Answer 417

wild species that are adapted to the environment can survive. isolated wild species can reproduce because only single parent is required. crop plants are genetically identical therefore they have the same yield and characteristics. require less energy. quick no gametes favourable characteristics of parent passed on dense colonies outcompete other species no pollinators required reliable no harmful variation

Answer 418

less variation lack of diversity in wild plants risk of overpopulation in wild plants competition for resources as all individuals are close together in wild plants wild plants and crops are less likely to survive to change environment no adaptive features in wild plants all individuals are susceptible to the same, diseases/pests in wild plants higher risk of extinction in the wild plants no evolution in wild plants genetically identical so higher risk of inheriting genetic diseases in both wild and crop plants

Answer 419

process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other.

Answer 420

fusion of the nuclei of gametes.

Answer 421

is diploid

Answer 422

maintain/ increase, the population in wild plants allow variation in wild plants allow adaptation to, new/ changed environment(s) in wild plants allow natural selection/ evolution/ formation of new species in wild plants random fusion of gametes in wild plants ability to express recessive trails in wildplants allows to use of selective breeding in crop plants

Answer 423

Slow Lots of energy is needed Need 2 parents

Answer 424

Protect the flower while it is a bud

Answer 425

Brightly coloured and attract insects to flowers

Answer 426

It is male part of flower, consists of long filament and anther at the top which contain pollen grain, which contain male gametes

Answer 427

It is the female part of flower. It contains ovary, which contains ovules, which contains female gamete. At top is style with stigma at the top. function of stigma is to catch pollen grains.

Answer 428

large, brightly coloured petals, strong scent, nectar to attract insects towards them. The anther and stigma are inside the flower so that the insect brush past them and some pollen stick onto them. The insect then goes to another flower, looking for more nectar. Pollen grains are sticky and spiky so, some of the pollen it picked up at the first flower sticks onto the stigma of the second flower when the insect brushes past it. The stigma is sticky, and many pollen grains get stuck on it.

Answer 429

produce much more pollen than insect pollinated flowers. This is because a lot of the pollen doesn’t land on another flower, so huge amounts are wasted. Usually no petals because there is no need to attract insects. Their anthers and stigmas dangle outside the flower, to catch the wind. The filaments of the anthers are very flexible, so they can swing in the wind and release their pollen. The feathery stigmas have a large surface area, increasing the chances of catching pollen.

Answer 430

transfer of pollen grains from an anther to a stigma.

Answer 431

transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the same plant.

Answer 432

transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species.

Answer 433

lots of variation. Less capacity to respond to changes in the environment. They don’t rely on pollinators

Answer 434

variation. More capacity to respond to changes in the environment. They rely on pollinators.

Answer 435

a pollen nucleus fuses with a nucleus in an ovule

Answer 436

A pollen lands on stigma pollen (grain) germinates/ pollen (grain) grows pollen tube pollen tube grows down the style reaches the ovule (tip of) pollen tube breaks open male gamete travels down the pollen tube male gamete enter ovule (male gamete) fuse with female gamete zygote forms.

Answer 437

zygote (is formed) divides by mitosis to form embryo formation of radicle and plumule formation of, cotyledons/ seed leaf/ food reserve formation of teste/ seed coat ref to endosperm seed formed form ovule

Answer 438

testes, as well as providing a sort of climate control system

Answer 439

sperm away from testis, it then join up with the urethra just below the bladder

Answer 440

can carry both urine and sperm at different time

Answer 441

makes semen, a fluid in which sperm can swim in.

Answer 442

to enter the vagina and release sperm.

Answer 443

eggs or egg cells.

Answer 444

egg to uterus.

Answer 445

nourish the developing fetus prior to birth

Answer 446

allows fluids to pass between uterus and vagina

Answer 447

the site where sperms are placed after ejaculation

Answer 448

male gamete (sperm) and a female gamete (egg cell).

Answer 449

flagellum to swim lots of mitochondria to provide energy for swimming by respiration. enzymes in the acrosome to digest its way through the jelly coat.

Answer 450

energy store to provide energy and nutrients for the growth and development of zygote after fertilisation. jelly coat hardens after the entry of one sperm to prevent entry of multiple sperms.

Answer 451

Sperm cells are lot smaller than egg cells. Sperm cells are streamlined and egg cells are round. Sperm cells can move by themselves but egg cells cannot. There are millions of sperms deposited at the vagina but there are maximum of 2 egg cells in female reproductive system.

Answer 452

the zygote forms an embryo which is a ball of cells that implants into the lining of the uterus.

Answer 453

embryo to wall of uterus. Placenta is where substances are exchanged between the mother’s blood and the embryo’s blood.

Answer 454

gas exchange transfer of dissolved nutrients, from maternal (circulation)/ to fetal. transfer of excretory products, from fetal/ to maternal; by diffusion produces/ secretes, (named) hormones; passive immunity/ antibodies, from maternal/ to fetal prevents/ limits, mixing of blood regulating blood pressure maternal/ fetal attachment point red to counter current flow/ maintains concentration gradient

Answer 455

protection from (mechanical) shock (of fetus) maintains (constant) temperature (of fetus) allows movement (of fetus) prevents dehydration

Answer 456

maintains temperature ; mechanical shock protection ; allows movement (of the fetus) ; provides support (of the fetus) ; provides a sterile environment / prevents infections ; (movement) allows for development of bones and muscles ; ref. to swallowing (of fluid) ; lubrication / AW ;

Answer 457

the placenta and affect the fetus

Answer 458

secondary sexual characters to develop in boys, like growth of facial hair and pubic hair, broadening shoulders and general muscular development and a deepening voice

Answer 459

cause the secondary sexual characters to develop in girls, like increase in size of breast, growth of pubic hairs, hips become wide

Answer 460

ovaries. After ovulation site of progesterone production is corpus luteum. During pregnancy site of progesterone production is the placenta.

Answer 461

loss / thinning, of lining (of uterus), at the beginning of the cycle / during first week / between day 1–7 ; regrowth / thickening of, lining (of uterus), during second week / after loss (of lining) / before ovulation ; thickness of lining remains constant, in the last two weeks / at the end of the cycle / after ovulation / if no fertilisation ;

Answer 462

FSH stimulates, development / growth / maturation, of follicles (in ovary) ; -FSH stimulates, development/growth / maturation, of, egg (cell) / ova / ovum / (female) gamete(s) ; -FSH stimulates, production / release / secretion, of oestrogen (from ovary) ;

Answer 463

(FSH and) LH (surge) stimulates, ovulation / release of egg from ovary LH stimulates (corpus luteum / yellow body / empty follicle), secretion / production / release, of progesterone decrease in LH decreases secretion of progesterone (by corpus luteum) ;

Answer 464

Stimulates the uterus to develop a lining (to replace the lining lost during menstruation) Post-ovulation, inhibits FSH and LH production in the pituitary gland.

Answer 465

maintains and thickens lining of the uterus inhibits FSH and LH production if fertilisation doesn’t occur, levels drop and menstruation occurs.

Answer 466

is an infection that is transmitted through sexual contact.

Answer 467

is a pathogen that causes an STI.

Answer 468

sexual contact sharing contaminated needles sharing contaminated syringes blood transfusion breast milk tissue/ organ transplant

Answer 469

never have more than one sexual partner use condoms

16. Reproduction Flashcards

(510 cards)