Science - 2 Flashcards
1
Q
What type of cell division produces 4 haploid daughter cells?
A
Meiosis
2
Q
Where does meiosis and mitosis occur?
A
Meiosis - testes and ovaries
Mitosis - Nearly every cell
3
Q
Where does fertilisation typically occur?
A
Fallopian tubes or oviducts
4
Q
What are mutations and some examples?
A
Any change in the DNA sequence of a cell. Examples - UV light, Gamma rays, and cigarette smoke
5
Q
What is and example of a diploid cell and how many chromosomes?
A
A zygote and 46 chromosomes
6
Q
What are the three stages of a baby in utero?
A
zygote, embryo, fetus or foetus
7
Q
What are the 5 main parts of a female reproductive system?
A
oviduct or fallopian tubes, ovary, uterus, cervix, and vagina
8
Q
What are the male gametes
that produce sperm?
A
Testes
9
Q
What adds fluids and nutrients to sperm to produce semen?
A
Prostate gland
10
Q
What is the distance travelled by an object per unit of time?
A
Velocity
11
Q
What is the number of seconds it takes for an object to travel a certain distance?
A
Time
12
Q
What is the product of speed and time?
A
distance
13
Q
Unit for work
A
Joules ( J )
14
Q
Unit of power
A
Watts ( W )
15
Q
Unit of weight
A
Newtons ( N )
16
Q
How many chromosomes are in a normal human cell?
A
23
17
Q
Order gene, chromosome, base pair, and nucleus from smallest to biggest
A
chromosome, base pair, gene, nucleus
18
Q
What are the two base pairs?
A
- GC
- AT
19
Q
what is the dependant variable?
A
What you measure/change
20
Q
What is the independant variable?
A
Thing that stays the same
21
Q
What is the scrotum?
A
The part outside of the testes that basically looks after it
22
Q
why do genes and gamets half during meiosis
A
Too many chromosomes, makes sure we have 2n or diploid cells
23
Q
who proposed the theory of evolution by natural selection
A
Charles Darwin
24
Q
What is the order of survival of the fittest?
A
Variation, survival, adaption, reproduction, evolution
25
What is weight and mass measured in and how do you get weight (N) to mass on earth(kg)?
Weight - N
Mass - Kg
Weight x 10 = weight on earth
26
What / where is the line of best fit?
-Does not go through first and last point
-has same number of crosses on both sides of the line
27
What does a triangle mean in a formulae?
Change in
28
What is mitosis?
Mitosis is a type of cell division that results in two daughter cells with identical genetic material to the parent cell.
29
What is meiosis?
Meiosis is a type of cell division for sexual reproduction, resulting in four daughter cells with half the number of chromosomes as the parent cell. It makes sure we are all different.
30
How many chromosomes are there in a sperm cell?
23
31
The section of DNA that is responsible for one particular inherited trait is called a
Gene
32
Where and what are the forces called pulling the object downwards and upwards?
Support force (up), weight force (down)
33
What are thread-like structures that contain genes in the nucleus called?
Chromosomes
34
What are gametes?
Gametes are sex cells (sperm in males, eggs in females) that fuse during fertilization, creating a zygote with a complete set of chromosomes from both parents.
35
unit for mass
kg
36
Dominant allele meaning?
the relationship between two versions of a gene
37
Recessive allele meaning?
the relationship between an observed trait and the two inherited versions of a gene related to that trait
38
What are testes?
Where sperm and testosterone is made
39
What are sperm ducts?
Transfers mature sperm to urethra in preparation for ejaculation
40
What is a prostate gland?
Makes seminal fluid that contains nutrients to keep sperm healthy
41
What is uretha?
The tube through which urine and semen exit the body
42
What is penis?
The male external sex organ
43
What are ovaries?
Stores and releases eggs (ovum - plural = ova)
44
What are oviducts?
Connects ovary to the uterus
Where fertilisation occurs
45
What is a uterus?
Where the foetus develops
46
What is a cervix?
Opening between uterus and vagina
47
What is a vagina ?
Tube that runs between cervix and the vulva (external female sex organ)
48
What are gametes?
A gamete is a male/female sex cell that can fertilise during sexual reproduction to form a zygote
eg. Male - sperm, Female - ovum/egg
49
What is the development from a zygote ?
to an embryo and then a fotus
50
Where is the location of DNA?
Genes in a cell
51
o
52
What is a mutation?
A change in genetic code
53
Brief description of cells
All cells (expect gametes) have 2 genes / allels for each characteristic
54
What is variation and what causes it?
Genes and environment
55
Describe mitosis
normal cell devision (genetically identical)
56
Describe meiosis
cell division important for sexual reproduction
57
Describe the two types of variation
discrete and continuous in answer
58
Define evolution
cumulative change in the heritable characteristics of a population over time
59
What is the importance of variation as a key feature of natural selection?
mutations, environmental influences, genes/different allels (dominant or reccessive), meiosis
60
Explain evolution
evolution led to diversification of species like a tree, not a ladder
61
What happens during fertilisation?
The fusing of gametes
The sperm's nucleus fuses with the egg's nucleus to form a zygote
Occurs in the fallopian tube
62
Describe Embryo development
Zygote travels down the fallopian tube
Divides to become an embryo and implants in uterine wall
Placenta/Umbilical cord provides oxygen and nutrients to the foetus, and removes CO₂
Foetus develops; exits through vagina
63
describe haploid cells
Contains 1 set of chromosomes (23)
Produced by meiosis
n (only one type)
gametes (eg. sperm/ovum)
64
describe diploid cells
Contains 2 sets of chromosomes (46)
Produced by mitosis
2n (one from mother, one from father)
body cells (eg. skin, liver, lungs)
65
Show the link between DNA, genes and chromosomes
The DNA double helix coils up to form a chromosome, each chromosome contains a number of genes
66
State the location of DNA/genes in a cell
DNA is mainly found in the nucleus of a cell
Multiple genes are found in a chromosome, which is formed by coiled up DNA
67
Give a brief description of DNA
molecule that carries our genes
68
Explain what the human genome is
Genome is all of an organism’s DNA, so a human genome is all of someone’s DNA
69
Explain the importance of DNA making exact copies of itself
Ensures for the exact replication of genetic information, preserving genetic traits
70
Define a mutation as a change in genetic code
A permanent change in the base sequence of DNA
Can lead to the formation of new alleles, which result in different proteins being produced
71
Give examples of mutations
Cystic Fibrosis, Haemophilia, Sickle Cell Disease
72
List the causes of mutations
UV radiation, chemicals, diet, solar radiation
73
Give examples of how mutations can be useful or harmful
Mutations can be useful in humans for stuff like disease resistance, but can be harmful due to things like cancer, sickle cell disease, haemophilia etc.
Mutations also allow a species to adapt to an enviroment
74
Define Genotype
For every gene, an organism inherits an allele from each parent. These might be the same, or might be different
An organism's genotype is the set of alleles that it carries - normally represented by upper/lowercase letters
75
Define phenotype
An organism's phenotype is its physical characteristics
Phenotype is the expression of the organism's genotype
76
What do all cells except gametes have?
All cells have 2 genes for each characteristic - one from the mother and one from the father
77
Deference between dominant and recessive allels?
If you have a dominant allele, it will always show up in your phenotype Recessive alleles will only how in your phenotype if there is no dominant allele present
78
what is Homozygous DOMINANT genotype (TT)
Where alleles from both parents are dominant (homo means same)
79
what is Heterozygous genotype (Tt)
Even though you have a recessive allele in this genotype, the dominant allele trumps over the recessive allele.
80
what is. Homozygous RECESSIVE genotype (tt)
Where alleles from both parents are recessive
81
What is variation?
Variation is the differences between individuals. It is caused by an individual's genes and environment
eg. diet, culture, pollution
82
Describe discrete variation
distinct categories
usually represented by a bar graph
eg. blood groups (A, B, AB, O), tongue rolling (yes/no)
83
Describe continuous variation
No distinct categories
Usually represented by a line graph
eg. height, weight, heart rate
84
Describe mitosis
A process of nuclear reproduction in body cells that produces two daughter cells that are genetically identical to the parent cell.
85
Describe meiosis
A process of reduction division in which the chromosome number is halved from diploid to haploid, resulting in genetically different cells.
Meiosis is used to produce gametes
86
Define evolution
The change in adaptive features of a population over time as the result of natural selection
87
explain selective breeding
Involves humans choosing organisms with desirable characteristics to breed together and produce offspring with more desirable characteristics.
88
What is Natural selection
When organisms that are fitter tend to survive and produce more offspring, passing their alleles onto the next generation
89
Explain that evolution led to diversification of species like a tree, not a ladder
Species evolve from a common ancestor, not linearly
90
What is Evolutionary fitness
Natural variation means that some individuals are more successful than others
They have inherited features (adaptations) that increase their fitness
91
describe fitness
probability of surviving and reproducing in environment in which organisms are found
92
what is scientific theory?
Explanation for a particular phenomenon, supported by evidence
