prac exam Q for repro

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What is the relationship between the DNA content found in a skin cell and ovum? Give an explanation for this difference.

DNA content in ovum is half that of a skin cell

Ovum is a gamete that is haploid/ contains only half the number of chromosomes

Skin cells are diploid so would contain double the DNA

The process of meiosis is involved in the production of gametes. What are the two forms of gametogenesis called and explain how they differ in the number of gametes they produce.

Spermatogenesis, produces 4 sperm cells, Oogenesis, one egg cell is produced along with 3 polar bodies

(d) Sperm production occurs within the testes. Name the structure in which this process takes place and give an advantage of this structure being tightly coiled.

Seminiferous tubules Increases area for sperm production

State two structural differences between a sperm and an egg and for each difference explain how it helps in the process of reproduction.

<ol> <li>Difference: sperm has tail, ovum doesn’t Explanation: for movement through female reproductive tract 2. Difference: Ovum has more cytoplasm than sperm Explanation: contains all organelles for cell functioning</li> <li>Difference: Sperm has acrosome, helps sperm penetrate ovum</li> </ol> Signup and view all the answers

Explain the importance of fertilisation in sexual reproduction.

Combines genetic material from two different parents/male and female parents/egg and sperm Restores diploid number of chromosomes Creates variation Signup and view all the answers

Most assisted reproductive technologies require the woman to take a fertility drug. Often these drugs contain follicle-stimulating hormone. Using your knowledge of the ovarian cycle in females explain what the purpose of this hormone would be in treating infertility.

FSH acts on follicles in ovary to begin growth and maturation of follicles Increased levels of FSH may enable more than one follicle to mature at a time increases amount of eggs that can be harvested each cycle/ released at ovulation. Signup and view all the answers

explain role of hCG in pregnancy

Maintains the corpus luteum So that progesterone and oestrogen are secreted Until placenta is established Signup and view all the answers

Describe how the foetal blood system is kept separate from that of the mother.

Chorionic villi are surrounded by pools of mother’s blood 1 Layers of cells separate two blood supplies 1 Signup and view all the answers

Totipotent? where?

zygote, can differentiate into any type of cell Signup and view all the answers

multipotent? where?

can become a cell of a particular tissue, embryos/adult tissue Signup and view all the answers

pluripotent? where?

can become several types of cells, inner cell mass/blastocyst Signup and view all the answers

Many vital organs of a foetus are not required to function whilst it is carried in the uterus. After birth, however, rapid changes need to occur within the foetal circulation to enable the baby to survive outside the womb. Outline two major changes (besides the hole in the heart closing), that will occur.

Blood flow through ductus arteriosus (lung bypass) decreases 1 Blood now flows to the lungs via the pulmonary artery 1 Blood flow through ductus venosus (liver bypass) decreases 1 Blood starts to flow through the liver and returns to heart via the inferior vena cava 1 Signup and view all the answers

Occasionally a baby is born with a serious condition of the heart. There are separate abnormalities within the heart that occur as a result of this condition including that the aorta comes primarily out of the right ventricle instead of the left and the muscular wall between the right and left sides of the heart is incomplete, so the blood in the left and right ventricles is not kept separate. In a baby with the condition described above, is the hole between the ventricles an advantage or a disadvantage? Explain your choice.

advantage, hole allows for some mixing of oxygenated and deoxygenated blood to go to right ventricle, this blood that does contain some oxygen can then be pumped to the body via the misplaced aorta. Signup and view all the answers

how does progesterone affect uterine lining during monthly cycle

endometrium continues to thicken until fully developed and then is maintained, glands secrete mucous, drop in progesterone induces menstruation, endometrium becomes more vascular Signup and view all the answers

how does oestrogen affect uterine lining during monthly cycle

inhibits menstrual flow triggers growth and repair of endometrium Signup and view all the answers

how does fertilisation of an egg alter the hormonal regulation of menstrual cycle?

corpus luteum continues to secrete progesterone (and oestrogen) progesterone maintains endometrium the release of progesterone and oestrogen inhibits the secretion of FSH from anterior pituitary gland hence no more follicles in ovary begin to mature Signup and view all the answers

About 1 in 6 couples in Australia wanting to have children experience difficulties in getting pregnant. Advancements in reproductive technology have resulted in a range of treatments for infertility being made available. One such assisted reproductive technology is GIFT.

What does GIFT stand for?

gamete intra fallopian transfer Signup and view all the answers

describe how gamete intra fallopian transfer takes place

gametes from the mother and father are inserted into the mother's fallopian tube Signup and view all the answers

define stem cell

cell that is not specialised cell capable of repeated mitosis cell can differentiate into specialised cells Signup and view all the answers

differences between adult and embryonic stem cells

adult: multipotent embryonic- pluripotent adult: taken from adult tissue/s embryonic: cultured from frozen embryos adult: its stem cells are not rejected embryo: may be rejected by recipient's body embryo: more ethical issues linked to use of embryonic stem cells adult: cells derived from patient's own tissue so no real ethical concerns Signup and view all the answers

explain functions of placenta during pregnancy

secretes hormone (hCG), which maintains corpus luteum, and the corpus luteum secretes oestrogen and progesterone to maintain pregnancy by maintaining the endometrium removes wastes by transporting urea, uric acid and ammonia from foetus to mother;s kidneys allows for transmission of antibodies from mother to foetus to give foetus immunity from pathogens/disease transports nutrients such as glucose and amino acids to foetus for growth stores essential nutrients to release later on when demand for them by foetus is greater transports oxygen from mother to foetus to enable cell respiration to occur in foetus' cells transports waste products of cellular respiration/carbon dioxide from foetus to mother so it doesn;t poison cells increases surface area available for exchange of wastes and nutrients so that faster diffusion will occur, hence increasing efficiency Signup and view all the answers

how do contraceptive oral pills work to prevent pregnancy

hormones taken in pill form for 21 days substitute hormones prevent release of mature egg from ovary cervical mucus becomes thick and sticky so sperm unable to travel to uterus alter lining of uterus so less receptive to embryo implanting Signup and view all the answers

how to condoms work to prevent pregnancy

made of rubber rolled onto penis before intercourse prevents semen from entering vagina Signup and view all the answers

advantages of pills

reduce menstrual cramps reliable reduced incidence of cervical or ovarian cancer reduce PMT (premenstrual tension) convenient Signup and view all the answers

condom advantages

easy to buy cheap reliable if used correctly protects against STIs Signup and view all the answers

pill disadvantages

must be taken at same time each day can have side effects need to get a prescription some are expensive Signup and view all the answers

condom disadvantages

may reduce male sensation both partners have to be cooperative Signup and view all the answers

describe the changes involved from the formation of the zygote to its implantation in the uterine wall of the mother.

zygote forms in fallopian tube when sperm fertilises egg (1) under goes mitosis (1) becomes a morula (solid ball of cells) (1) becomes a blastocyst (hollow ball of cells surround a fluid-filled cavity with an inner cell mass (embryoblast- 30 cells) (1), enters uterus where it remains for 2-3 days (1), forms an inner cell mass (1) surrounded by amnion and chorion (1), attacked to uterine wall firmly to gain nourishment-implantation (1), inner cell mass forms three embryonic layers/develops into embryo composed of stem cells. Signup and view all the answers

what does endoderm give rise to

epithelium of organs in respiratory system (lungs, bronchi, trachea), epithelium of alimentary canal (stomach, intestine), epithelium of thyroid Signup and view all the answers

what does mesoderm give rise to

epithelium of kidney, dermis of skin, connective tissue, blood, smooth, striated, cardiac muscle, lymphatic system , reproductive and excretory organs Signup and view all the answers

what does ectoderm differentiate into

epidermis of skin, epithelium of mouth, central nervous system, teeth enamel, cornea/retina/lens of eye Signup and view all the answers

identify environmental factors that can affect the development of the fetus. use examples to illustrate how the environmental factor stated can affect development of foetus.

second-hand smoke, mother's diet (alcohol, drugs, medicinal products, raw meat/fish), viral infections, lead and other pollutants. ingestion of too much alcohol can cause fetal alcohol syndrome (physical abnormalities, cognitive disabilities, mental health issues) lead accumulation can lead to the damage of the developing CNS Signup and view all the answers

how does raw meats/fish impact development of fetus

contains listeria bacteria, which can cause miscarriage or stillbirth Signup and view all the answers

whats thalidamide and how does it affect foetus

originally used as morning sickness pill, but links to severe birth defects as it affects growth and development of limbs. Signup and view all the answers

chromosonal analysis technique performed on fetus to detect genetic condition caused by non-disjunction: amniocentesis. how it works, risks involved, limitations, and what other disorders can be detected thru this technique

removal of amniotic fluid (week 16-20) from amniotic sac (10-20mL) 1 floating in fluid are living cells of fetus (1) detect chromosomal abnormalities (down syndrome, neural tube defects, genetic disorders) OTHER DISORDERS: identify BIOCHEMICAL DEFECTS RISK: infection, miscarriage, damage to baby LIMITATION:: cannot identify all genetic diseases Signup and view all the answers

chorionic villus sampling. how it works, risks, limitations

obtain fetal cells from chorion and exam same way as amniocentesis test take place week 9-19 of pregnancy quick procedure OTHER DISORDERS: genetic disorders and biochemical abnormalities RISK- miscarriage LIMITATION: cannot pick up spina bifida Signup and view all the answers

how fetal blood sampling works, risks associated, genetic disorders can detect, limitations

obtain fetal blood samples from placenta directly obtainable quick procedure and diagnosed on the day reduced risk of miscarriage OTHER DISORDERS: fetal haemolytic abnormalities, intrauterine infection, growth retardation, birth defects, metabolic disorders -minimal limitations, but may not detect all congenital abnormalities Signup and view all the answers

the dominant hormone controlling the secretory phase of the menstrual cycle is...

progesterone Signup and view all the answers

the main hormone(s) at work in initiating labour is..

oestrogen and oxytocin Signup and view all the answers

In the placenta, the mother’s blood and the fetal blood flows in opposite directions. This is important because this counter current flow will

build up concentration gradient all the way along the capillary to facilitate diffusion Signup and view all the answers

The use of the rhythm method as an effective use of contraception relies on

(d) monitoring a woman’s fertility and menstrual cycle. Signup and view all the answers

whats blastulation

the process during early embryonic development that follows fertilization and cleavage. It involves the formation of a structure known as the blastula from the fertilized egg (zygote). This process typically occurs in the early stages of development, around 5-7 days after fertilization in humans. Signup and view all the answers

During blastulation, which structure releases hormones that maintain the endometrium ready for implantation?

corpus luteum Signup and view all the answers

what type of stem cells make up the inner cell mass/embryoblast

pluripotent Signup and view all the answers

Placental abruption is a condition where the placenta begins to come away from the wall of the womb. Describe one effect this may have on the growing foetus. (2 marks)

oxygen not supplied to foetus and carbon dioxide isn't removed, can cause stillbirth, Signup and view all the answers

Patent foramen ovale (PFO) is the name given to the incomplete closure of the hole between the two atria in the heart of newborns. Discuss the importance of the foramen ovale in foetuses and the possible implications of PFO.

foramen ovale allows blood to bypass the lungs (1) as the lungs are not functioning (1) implications: shortness of breath, bluish skin of baby, heart palpitations Signup and view all the answers

describe how in-vitro fertilisation (IVF) differs from natural fertilisation and discuss the risks involved in IVF

fertilisation occurs outside the body of a female rather than inside after fertilisation dividing cells are transferred to the mother rather than fertilisation occuring inside the fallopian tube risks: ectopic pregnancy, miscarriage, premature births Signup and view all the answers

Study Notes

DNA Content in Skin Cell vs. Ovum

Skin cells are diploid containing two sets of chromosomes, while ova are haploid with one set of chromosomes.
This difference arises from meiosis, which halves the chromosome number in gametes for sexual reproduction.

Forms of Gametogenesis

Spermatogenesis develops sperm, producing four functional gametes per cycle.
Oogenesis develops ova, yielding only one mature ovum from each cycle, with three polar bodies that are non-functional.

Sperm Production in Testes

Sperm production occurs in the seminiferous tubules, which are coiled structures enhancing surface area for efficient spermatogenesis.

Structural Differences in Sperm and Egg

Sperm are motile with a flagellum, enabling them to reach and fertilize the egg.
Eggs are larger and contain nutritive yolk, providing essential nutrients for early embryonic development.

Importance of Fertilization

Fertilization combines genetic material from sperm and ovum, ensuring genetic diversity in offspring and initiating developmental processes.

Role of Follicle-Stimulating Hormone (FSH)

FSH stimulates ovarian follicle maturation, promoting ovum development and aiding in the treatment of infertility by enhancing egg production.

Role of Human Chorionic Gonadotropin (hCG)

hCG maintains the corpus luteum, ensuring continued production of progesterone, crucial for sustaining pregnancy in the early stages.

Separation of Fetal Blood System from Mother

The placenta serves as a barrier between maternal and fetal blood, preventing direct mixing while facilitating nutrient and gas exchange.

Stem Cell Potency

Totipotent stem cells can develop into any cell type, found in early embryos.
Multipotent stem cells have a limited capacity, such as hematopoietic stem cells in bone marrow.
Pluripotent stem cells can differentiate into almost any cell type, present in embryonic stem cells.

Changes in Fetal Circulation at Birth

Closure of the ductus arteriosus redirects blood flow to the lungs.
Closure of the foramen ovale ensures separation of oxygenated and deoxygenated blood.

Heart Condition with Ventricular Septal Defect

The hole between ventricles could be a disadvantage, allowing unoxygenated blood to mix, impairing the baby’s oxygen supply.

Progesterone Effects on Uterine Lining

Progesterone thickens and maintains the uterine lining, preparing it for potential implantation after ovulation.

Oestrogen Effects on Uterine Lining

Oestrogen promotes growth and repair of the uterine lining, facilitating a suitable environment for implantation.

Hormonal Regulation Alteration Post-Fertilization

After fertilization, hormone levels change, particularly with elevated hCG, which supports the luteal phase and prevents menstruation.

Gamete Intra-Fallopian Transfer (GIFT)

GIFT stands for Gamete Intra-Fallopian Transfer, involving the placement of both sperm and eggs directly into the fallopian tubes for fertilization.

Stem Cell Definition

Stem cells are undifferentiated cells capable of self-renewal and differentiation into various specialized cell types.

Differences Between Adult and Embryonic Stem Cells

Adult stem cells are limited in differentiation and primarily serve to replace damaged cells; embryonic stem cells are pluripotent and can generate any cell type.

Functions of the Placenta During Pregnancy

Provides nutrients and oxygen to the fetus, removes waste products, and produces hormones that support pregnancy.

Oral Contraceptive Pills

Work by releasing hormones to inhibit ovulation, thicken cervical mucus to block sperm, and thin the uterine lining.

Condoms as Contraceptives

Act as physical barriers to prevent sperm from entering the uterus, reducing the chance of fertilization.

Advantages of Oral Pills

High effectiveness rate, ease of use, and can regulate menstrual cycles.

Advantages of Condoms

Provide protection against sexually transmitted infections (STIs) and do not require a prescription.

Disadvantages of Pills

Possible side effects include hormonal imbalances and increased risk of blood clots; requires regular intake.

Disadvantages of Condoms

Can reduce sensitivity; potential for breakage or slippage, requiring proper use for effectiveness.

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Description

Explore the fundamental differences in DNA content between skin cells and ova. This quiz delves into the biological significance of these differences and their implications for cellular function and reproduction.