Reproduction Flashcards
1
Q
What is the function of the testes?
A
The testes produce sperm and testosterone.
2
Q
What is the sperm duct?
A
It is the tube that carries sperm where it mixes with seminal fluid.
3
Q
What is semen?
A
It is a combination of sperm and seminal fluid.
4
Q
What is the function of seminal fluid?
A
It provides the sperm with nutrients.
5
Q
What happens during ejaculation?
A
Semen travels along the urethra and exits the body through the penis.
6
Q
What are the two functions of the penis?
A
It passes semen out during ejaculation and also passes urine out of the body.
7
Q
What are female gametes called?
A
Ova.
8
Q
Where are ova produced?
A
In the ovaries.
9
Q
What happens when an egg matures?
A
It is released into the oviduct.
10
Q
What is the oviduct also known as?
A
The fallopian tube.
11
Q
What lines the oviduct?
A
Ciliated epithelial cells.
12
Q
What is the role of cilia in the oviduct?
A
They move and sweep the ovum along the tube.
13
Q
Where does fertilisation occur?
A
In the oviduct.
14
Q
What happens if the ovum meets a sperm cell?
A
Fertilisation occurs.
15
Q
What is a fertilised egg called?
A
A zygote.
16
Q
What happens to the zygote after fertilisation?
A
It implants in the uterine lining and develops into an embryo.
17
Q
What happens if fertilisation does not occur?
A
The uterine lining is shed during menstruation.
18
Q
What is the cervix?
A
A circular ring of muscle at the end of the uterus that keeps the baby in position during pregnancy.
19
Q
What does the vagina connect to?
A
It leads from the cervix to the outside of the body.
20
Q
What is the function of the vagina?
A
It holds the penis during sexual intercourse.
21
Q
What is the urethra?
A
A separate tube from the vagina that allows urine to pass out of the body from the bladder.
22
Q
What is formed when a sperm and egg cell fuse?
A
A fertilised egg or zygote.
23
Q
What does the zygote become?
A
It divides by mitosis into an embryo.
24
Q
Where does the embryo implant?
A
Into the wall of the uterus.
25
What is the function of amniotic fluid?
It cushions the baby and acts as a shock-absorber protecting the embryo.
26
What connects the embryo to the placenta?
The umbilical cord.
27
What is the function of the placenta?
It anchors the baby in the uterus and exchanges substances like oxygen and glucose while removing waste like carbon dioxide.
28
What is a gene?
A section of DNA which codes for a protein.
29
Where are genes located?
On chromosomes within the nucleus.
30
What do genes provide?
Instructions on how to make proteins.
31
What shape does a DNA molecule have?
A double helix.
32
What is a genome?
The entire DNA within an organism.
33
What was the Human Genome Project?
A project started in 1990 to identify every base in human DNA.
34
How long did the Human Genome Project take?
13 years.
35
How has the Human Genome Project helped medicine?
It has enabled scientists to find disease-linked genes understand and treat genetic disorders and trace human migration patterns.
36
What is DNA?
A polymer made up of long chains of nucleotides bonded together.
37
What is each nucleotide made of?
A sugar a phosphate group and a base.
38
What are the four bases found in DNA?
Adenine thymine guanine and cytosine.
39
Which bases pair together in DNA?
A pairs with T and G pairs with C.
40
Why do certain bases pair together?
Because their shapes are complementary.
41
If a DNA molecule has 20 percent guanine how much cytosine will it have?
20 percent.
42
Why does a DNA molecule have equal amounts of guanine and cytosine?
Because G and C are complementary base pairs.
43
If guanine and cytosine make up 40 percent of the DNA what percent is left for adenine and thymine?
60 percent.
44
How much adenine and thymine will there be if 60 percent is left?
30 percent of each.
45
What is the first step in the process of producing a protein?
Transcription.
46
Why is transcription important?
Because DNA is too large and wrapped around chromosomes to leave the nucleus.
47
What is the role of RNA in protein synthesis?
RNA acts as a copy of the gene's information and carries it from the DNA to the ribosome.
48
What are two important differences between RNA and DNA?
RNA is single-stranded and contains uracil instead of thymine.
49
What is the type of RNA that carries genetic information from DNA for protein synthesis?
Messenger RNA (mRNA).
50
Where does mRNA go after it is synthesised?
It leaves the nucleus and enters the cytoplasm.
51
What structure does mRNA go to in the cytoplasm?
Ribosomes.
52
What does a ribosome do with mRNA?
It reads the mRNA in codons to make a protein.
53
What is a codon?
A sequence of three bases in mRNA that corresponds to a particular amino acid.
54
What does tRNA do?
It carries amino acids to the ribosome based on the complementary anticodon.
55
What happens when the ribosome reads through the mRNA?
Amino acids are dropped off by tRNA molecules, forming a protein chain.
56
What happens to the protein chain after it is complete?
It folds into a unique shape that allows it to perform its function.
57
58
How do different RNA codons affect protein synthesis?
Different RNA codons code for different amino acids.
59
What does the sequence of bases in a gene determine?
The order of amino acids during protein synthesis.
60
What happens if a mutation occurs in the DNA base sequence?
It results in a change in the order of amino acids.
61
What could the result of a mutation in protein structure be?
The protein may have a different shape and may not work as effectively.
62
What is one example of a mutation affecting protein function?
A mutation in an enzyme may make it unable to bind to its substrate.
63
How common is it for a mutation to result in a loss of protein function?
It is rare for a mutation to cause a complete loss of protein function.
64
What happens to most mutations?
Most mutations have no effect or only a slight effect on the protein.
65
What do non-coding DNA regions do?
They can switch genes on and off.
66
What happens if there is a mutation in non-coding DNA?
It can affect the expression of other genes.
67
What are alleles?
Genes exist in alternative forms called alleles which give rise to differences in inherited characteristics.
68
What is an example of alleles in humans?
The gene for eye colour has alleles for blue, green and brown eyes.
69
How many alleles do we have for each gene?
Two alleles, one on each chromosome.
70
What is a genotype?
The combination of alleles that an organism possesses.
71
What is a phenotype?
The visible characteristics that an organism displays.
72
What is a dominant allele?
A dominant allele is always expressed, even if only one copy is present.
73
How can a dominant allele be described?
It 'decides' the characteristic that will be expressed from the gene.
74
What is a recessive allele?
A recessive allele is only expressed if both copies are present.
75
When can a recessive allele determine the characteristic?
When there is no dominant allele present.
76
How can a recessive allele be described?
It is the ‘weaker’ allele that only shows when both copies are inherited.
77
Do most characteristics come from a single gene?
No most characteristics are controlled by multiple genes.
78
What is an example of a polygenic trait?
Height is an example of a polygenic trait.
79
What is polygenic inheritance?
Polygenic inheritance is when several genes contribute to a phenotype.
80
What is monohybrid inheritance?
Monohybrid inheritance is the inheritance of one gene shown by a Punnett square.
81
Where are parent gametes written in a Punnett square?
On the side of the square.
82
Where are the genotypes of possible offspring written in a Punnett square?
In the centre of the square.
83
What do pedigree charts show?
They show how genetic characteristics are passed on through generations.
84
What are pedigree charts used for?
They help determine the probability of inheriting a genetic disease.
85
What do the symbols in pedigree charts represent?
They represent male, female, healthy and diseased individuals.
86
What do horizontal lines in a pedigree chart represent?
Two unrelated individuals who have reproduced.
87
What do vertical lines in a pedigree chart represent?
The offspring of a couple.
88
What does it mean if a disorder is inherited?
It means a parent has passed on a disease-causing gene to their offspring.
89
What is polydactyly?
A condition where an individual has extra fingers or toes.
90
What causes polydactyly?
A dominant allele of a gene that controls finger and toe number.
91
How many copies of the polydactyly allele are needed for it to be expressed?
Only one copy is needed.
92
What is cystic fibrosis?
A disorder where thick sticky mucus builds up due to faulty ion transport in cell membranes.
93
What causes cystic fibrosis?
A recessive allele that must be inherited from both parents.
94
What does it mean to be homozygous recessive for the cystic fibrosis gene?
It means having two copies of the faulty gene and expressing the disease.
95
What is embryo screening?
A procedure where cells from a developing foetus are tested for genetic abnormalities.
96
Why might parents choose embryo screening?
To check if their child is at risk of a genetic disorder.
97
What is one ethical concern about embryo screening?
It may lead to abortion which some people oppose.
98
Why do some people support embryo screening?
It can prevent children from being born with a poor quality of life.
99
What is a medical risk of embryo screening?
It increases the risk of miscarriage.
100
What is a false positive in embryo screening?
A healthy foetus is wrongly identified as having a disorder.
101
What is a false negative in embryo screening?
A foetus with a disorder is wrongly identified as healthy.
102
Why is cost a concern with embryo screening?
It is expensive but some argue it's cheaper than long-term treatment.
103
How many pairs of chromosomes do humans have?
Humans have 23 pairs of chromosomes.
104
Which pair of chromosomes determines sex?
The 23rd pair determines sex.
105
What are the sex chromosomes in females?
Females have two of the same sex chromosomes, XX
106
What are the sex chromosomes in males?
Males have two different sex chromosomes, XY
107
What does a Punnett square show about sex determination?
It shows there is a 50% chance of a child being male or female.
