exam questions I need to go over

Question 1

5 placenta roles

Answer 1

endocrine- hormones
excretory- waste
immune- antibodies
nutritional- nutrients
Respiratory -oxygen

Question 2

3 months growth

Answer 2

Forelimbs well developed; eyelids closed; outer ear completed; bone marrow formed; blood cells formed in bone marrow; sex distinguishable

Question 3

4 months growth

Answer 3

Arms and hands fully shaped; skeleton completed; exercising of muscles evident; ears stand out from head

Question 4

5 months growth

Answer 4

Fine hair covers body; gripping reflexes are developed; increased growth

Question 5

6 months growth

Answer 5

Respiratory movements; digestive glands begin to function; tooth buds evident; eyebrows and eyelashes

Question 6

7 months growth

Answer 6

Period of greatest growth; all systems functional except respiratory system

Question 7

8 months growth

Answer 7

Accumulation of fat beneath skin; growth slowed

Question 8

1. The first stage of labour

Answer 8

the dilation of the cervix is the time from the onset of labour to the complete dilation (or opening) of the cervix. With each contraction, the muscle fibres making up the uterus shorten a small amount, pulling on the cervix. This pull on the cervix shortens it so that it no longer projects down into the vagina. At the same time, the cervix is opened. This cervical dilation allows the foetus to move more deeply into the pelvis. As the contractions become more frequent and stronger, the head of the foetus is pushed more forcefully against the slowly dilating cervix.

Complete dilation of the cervix marks the end of the first stage of labour

Question 9

The second stage of labour

Answer 9

involves the delivery of the foetus and is often called the stage of expulsion. It frequently begins with the bursting of the membrane surrounding the foetus and a gush of fluid from the vagina.This distension of the vagina stimulates the woman to contract her abdominal muscles. These contractions, together with the contractions of the uterus, push the foetus through the vagina. Her pulse rate increases, and she usually begins to sweat from the effort required. Once the head has emerged, it turns sideways again to face the mother’s hips. This rotation allows the shoulders and the rest of the body to move more easily through the birth canal.

Question 10

Third stage of labour

Answer 10

Once born, the baby begins to breathe with its own lungs, even though it is still connected to the placenta by the umbilical cord. The amnion, chorion and placenta are still inside the uterus at this stage. The umbilical cord is clamped, tied in two places, and then cut between the ties The uterus continues to contract, and about five minutes after delivery the placenta, other membranes and the remains of the umbilical cord are expelled. Together these are called afterbirth. Little blood is lost during this stage as the placental blood vessels constrict and contractions of the uterus squeeze shut the uterine vessels that supply blood to the placenta

Question 11

Ductus venosus

Answer 11

The ductus venosus is a shunt that allows oxygenated blood in the umbilical vein to bypass the

Question 12

list three types of secretions produced by different cells lining the gastric pits

Answer 12

hydrochloric acid, mucus and pepsin

Question 13

list the 6 groups of nutrients

Answer 13

1. water
2. carbohydrates
3. lipids
4. proteins
5. minerals
6. vitamins

Question 14

what are organic compounds?

Answer 14

molecules that have a carbon chain.

Question 15

what activities take place in the proximal convoluted tubule/ loop of henle?

Answer 15

passive reabsorption of potassium, chloride and bicarbonate ions

Question 16

what activities take place in the distal convoluted tubule?

Answer 16

active reabsorption of sodium ions, water (depending on the body water needs). secretion of hydrogen and potassium ions, creatinine and certain drugs such as penicillin.

Question 17

what activities take place in the collecting duct?

Answer 17

active reabsorption of water, depending on bodies water needs.

Question 18

in glomerular filtration, what products are filtrate?

Answer 18

water
salts

amino acids 
fatty acids 
glucose 
urea 
uric acid 
creatinine 
hormones 
toxins 
various ions

–

Question 19

in reabsorption, what materials are reabsorbed?

Answer 19

water
glucose

amino acids
ions (sodium, potassium, calcium, chloride, bicarbonate)
some wastes are partially reabsorbed (urea)

Question 20

what are the properties of muscles?

Answer 20

• excitability
• contractibility
• extensibility
• elasticity

Question 21

structure of skeletal muscles (muscle bundles)

Answer 21

muscle cells are held together in muscle bundles

sheath of connective tissue (perimysium) surrounds each bundle to help it function as a unit

perimysium allows adjacent bundles to slide easily over one another as they contract

sheaths of connective tissue (epimysium) hold bundles together, towards the end of the muscle they taper and blend to form the tendon

Question 22

structure of muscle fibres

Answer 22

a muscle bundle is composed of muscle cells (muscle fibres) that lie parallel to each other in an elongated cylinder with many nuclei

around each muscle fibre is a thin, transparent plasma membrane (sarcolemma) containing cytoplasm (sarcoplasm)

between 10 and 100 micrometers in diameter and vary in length from a few mm to several cm

Question 23

structure of myofibrils

Answer 23

thread like structures found within the sarcoplasm of each fibre

lie parallel to each other and run the length of the fibre

tubular network called sarcoplasmic reticulum surrounds the myofibrils (a storage site for Ca2+, which is released to initiate muscle contraction)

each is composed of many smaller myofilaments, which are made up of protein - myosin and actin

Question 24

what are some important differences between DNA found in the nucleus and mtDNA?

Answer 24

nuclear DNA is in the form of very long strands that are bound to proteins, the histones.

mtDNA is in the form of small circular molecules that are not bound to proteins.

mtDNA is passed from mother to offspring and nuclear DNA is a combination of both the mother and father.

Question 25

explain the 5 steps of transcription

Answer 25

1. DNA unzips and RNA polymerase attaches to the template strand at a ‘start’ command.
2. RNA polymerase reads one triplet at a time, adding complementary nucleotides to form codons (uracil instead of thymine).
3. A ‘stop’ command (ATT) is reached and RNA polymerase detaches.
4. Newly formed mRNA strand detaches from the template strand and exists through nuclear pores.
5. DNA ligase reforms weak hydrogen bonds when the specific DNA is no longer needed

Question 26

what two enzymes are important in DNA replication?

Answer 26

DNA polymerase - enzyme that joins nucleotides together

DNA ligase - enzyme that joins the short sections of DNA together

Question 27

outline four differences between RNA and DNA

Answer 27

1. the sugar molecule is ribose, not deoxyribose. ribose has one more oxygen atom than deoxyribose.
2. RNA is single stranded, while DNA is double stranded.
3. RNA has bases cytosine, guanine, adenine and uracil. the structures of thymine and uracil are very similar, meaning that uracil is complementary to adenine.
4. the RNA strand is able to fold onto itself, forming hydrogen bonds between complementary bases.

Question 28

explain the 4 steps of translation

Answer 28

1. mRNA enters the cell cytosol and is attached to a ribosome.
2. The ribosome reads a codon at a time and recruits the tRNA molecule with the complimentary anticodon.
3. The tRNA molecule carries an amino acid, which forms a peptide bond with the AA before it.
4. The chain of peptides detaches and folds in a particular way to form a protein

Question 29

Emphysema

Answer 29

Damaged to alveoli walls
Reduction in surface area of respiratory surfaces
Reduction in oxygen entering blood
Limited respiration
Students may name another dysfunction e.g. pneumonia. Accept dysfunction with correct explanation.

Question 30

Describe the third stage of labour.

Answer 30

Umbilical blood vessels contract

Placenta is delivered

Question 31

Define co-dominance.

Answer 31

Both alleles dominant
Both traits expressed fully
Total

Question 32

Define sex-linkage

Answer 32

Allele carried on X chromosome

Not masked by the Y chromosome

Question 33

Outline three (3) functions of blood.

Answer 33

Transport oxygen/ nutrients around the body
Maintain pH
Maintain temperature
Protect against disease
Clotting 
Carries hormones/ chemical messengers

Question 34

Define that is meant by the word ‘organ’

Answer 34

Several types of tissue

Working together to achieve function

Question 35

GIFT: gamete intrafallopian transfer

Answer 35

A procedure where an egg retrieved from the body of a woman and sperm obtained from a male are both inserted back into the fallopian tube of a woman. Used when a female is having difficulty with implantation