Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology > SB3- Genetics > Flashcards

SB3- Genetics Flashcards

1
Q

What reproduction do do invertebrates do

A

Asexual reproduction is more common eg aphids produce offspring from cells formed in mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How to plants usually reproduce

A

Asexually

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does sexual reproduction do

A

Combines characteristics from both parents and so produces offspring different from eachother

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why are different characteristics an advantage

A

If the environment changes, variation means that there is a greater chance that some offspring will be better suited to new conditions and so will me more likely to survive and reproduce

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is asexual reproduction faster

A

There is no need to find a mate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What’s a zygote

A

When 2 gametes fuse during fertilisation

The zygote forms a ball of cells using a type of cell division called mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is DNA

A

It’s instructions for an organism found as code in a molecule called DNA

THE DNA of an organism is its genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What’s the human genome like

A

46 very long molecules of DNA and each molecule is inside a chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are genes

A

Along the length of a DNA molecule are sections that each contain a code for making protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How are proteins made

A

They are polymers made by linking different amino acids together in a chain

The order of amino acids is controlled by the gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What kind of cell does mitosis produce

A

Diploid cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What process is used to produce gametes

A

Meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Tell me about meiosis

A

Each chromosome replicates, the 2 copies remain making each chromosome look like an X, the 2 sets of chromosomes pair up forming 23 pairs then seperate into 2 new cells, next the 2 copies of a chromosome in each x shape split into 2 more new cells therefore produces 4 haploid daughter cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does meiosis create genetic variation

A

Each chromosome in each pair contains different versions of the same genes so they are genetically
Different chromosomes so explains why brothers and sister look similar but not identical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Tell me the order of meiosis

A 
Interphase 
Prophase
Anaphase
Telophase
Interphase
Metaphase
Anaphase
Telophase
Cytokinesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where is DNA stored

A

In the nuclei of a cell - each molecule of DNA is tightly coiled and packaged up with proteins to from chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What shape is DNA

A

A double helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 4 bases of DNA

A

Adenine, thymine, cytosine and guanine

Make them simple often call them A, T, C and G

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How are the bases arranged

A

In complementary base pairs

A and T always pair

C and G always pair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What’s a nucleotide

A

Each base is attached to a super and each sugar is attached to a phosphate group

The sugars and phosphate groups form the backbone of the DNA strands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How are bases joined together

A

Hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How many bonds are between the bases

A

Cytosine and guanine form 3 hydrogen bonds between them

Thymine and adenine only form 2 bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What makes our DNA different

A

The order of the bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What did Erwin Chargaff

A

He did chromatography experiments which showed the amount of A and T in an organisms DNA were the same, as were the amount of G AND C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What did Rosalind Franklin do
Took an X-ray photograph suggesting that DNA was a helix
26
What did Jerry Donohue do
Who showed them how DNA based could form hydrogen bonds
27
What's the genetic code
How the order of the DNA bases caused amino acids to be joined in a certain order on a protein
28
What's transcription
DNA bases are used to make a strand of RNA (ribonucleic acid) An enzyme called RNA POLYMERASE attached up the DNA IN front of a gene in a non-coding region (so called because it does not contain code for a protein) the enzyme separates the 2 DNA strands. The enzyme then moves along one DNA strand (the TEMPLATE strand) adding complementary RNA nucleotides. These contain the same bases as DNA except uracil (U) is used instead of thymine (T) the nucleotides link link to form a strand of RNA (mRNA)
29
What's translation
The mRNA strands travel out of the nucleus through nuclear pores, in the cytoplasm the mRNA strands attach to ribosomes A ribosome moves along the an mRNA strand three bases at a time (a codon) at each mRNA codon a molecule of transfer RNA (tRNA) with complementary bases line up- each tRNA molecule carries a specific amino acid, as the ribosomes moves along, it joins the amino acids from the tRNA molecules together, forming a polypeptide
30
What happens after translation
The polypeptide chain folds up to form a protein with a specific shape. Some proteins contain more that one polypeptide chain
31
What creates a mutation
A change In bases of a gene creates a genetic variant or mutation
32
How can a mutation be caused
When DNA is not copied properly in cell division. Environmental factors can also cause mutations Some mutations change an organisms phenotype (visible characteristics)
33
What are alleles - what do they mean
Mutations are the reason alleles exist - one gene can have many alleles, caused by different mutations. Your characteristics are shaped by the alleles you Inherit
34
What's haemoglobin like
It can 4 polypeptides of two kinds a and b (in those funny Greek letters) the polypeptides fold and join up to form a globular protein which carried oxygen.
35
What are mutations in non coding DNA like
RNA polymerase attaches to DNA bases in front of a gene, a mutation in this non-coding region may result in RNA polymerase not binding well - reducing transcription Other non coding mutations can result In RNA polymerase binding better and producing more mRNA
36
What are the 3 laws of inheritance according to Mendel
1) each gamete receives only one factor for a characteristic 2) the version of a factor that a gamete receives is random and does not depend on the other factors in the gamete 3) some versions of a factor are more powerful than others and always have an effect In the offspring
37
Why was mendels work largely ignored
Did not see how 'factors' could explain the many variations in characteristics such as human eye colour - couldn't see mendels ideas could explain evolution Argued that if the factors could boy change then a species would not evolve
38
What are alleles
Genes for the same characteristics but contain slightly different instructions that create variations eg brown and blue eyes
39
How is their genetic variation
There are 2 copies of every gene in each body cell - each copy of a gene may be a different allele, the different combinations of Alleles in different people gives us slightly different characteristics
40
What's homozygous
If both alleles for one gene are the same
41
What's heterozygous
if the alleles are different
42
What is dominat
It is the allele that has an effect
43
What's recessive
When an allele is in the genotype but not the phenotype
44
When is a recessive gene seen In phenotype
If both alleles are recessive, the recessive characteristics are seen
45
How is a dominant allele shown
With a capital letter Recessive with a lower case The dominant allele letter is always written before the recessive one The alleles in an organism are its genotype What the organism looks like is its phenotype
46
What do we use to explain the inheritance of one gene (monohybrid inheritance)
Diagrams, they predict the ratios of the phenotype
47
What are the sex chromosomes
They determined your sex Two types: X AND Y makes a male X and X makes a female
48
What chromosomes do gametes contain
Egg cells all contain X sex chromosomes and Sperms contain either X or Y
49
What are Punnett squares used for
They can demonstrate inheritance, they show possible genotypes They calculate the theoretical probability of offspring inheriting certain genotypes / used to calculate probabilities of different phenotypes caused by alleles Probabilities can be shown as a decimal or percentage
50
What does a family pedigree chart show
Shows how genotypes and their resulting phenotypes are inherited in families
51
What will happen if someone is given the wrong blood
The red blood cells in it will clump together which can kill
52
How do we classify blood
ABO blood group system In this system everyone's blood is one of 4 groups: A, B, AB, O
53
How is your blood group determined
By wether you have certain marker molecules on the outside of your red blood cells Three main types A, B and O
54
Tell me s let the genes in the ABO system
The gene that is responsible for the markers in the ABO system has 3 alleles, written as I (with a little letter (A,B, or O) above small like a power would be Everyone has 2 copies of the gene so may be homozygous for Any of the 3 alleles or heterozygous for any 2 of the three alleles I(with an O) is recessive to both I^A and I^B. However a person with genotype I^a I^b shows the effect of both alleles and has the blood group AB
55
What is codominance
When both alleles for a gene affect the phenotype eg blood group AB
56
What are sex linked genetic disorders
The Y chromosomes are missing some of genes in X chromosomes, so a man may only have 1 allele for some genes on the X chromosome, if the allele for one of these X chromosomes genes causes genetic disorder, then a man will develop that disorder Whereas if a women has a recessive allele for a disorder she won't get it as she still has a healthy allele with will be dominant So probability of a man developing it will be more than a women
57
Tell me some examples of a sex linked disorder
Red-green colour blindness - 8% men have it only 0.5% of women have jt A mother can be a carrier for the disorder which means she has one faulty allele and one normal allele
58
What is a mutation
A change in a gene that creates a new allele, often occur during cell division Happen Becuase there is a mistake in copying DNA during cell division More likely if there is damage to the DNA caused by radiation or certain substances Many mutations will not change a protein at all and so have no effect on phenotype
59
What can mapping a persons genome do
Indicate their risk of developing diseases caused by different alleles of genes, also help identify best medicines to treat a persons illness Becuase alleles we have can affect how medicines work in the body
60
How is genetic variation caused
By the different alleles inherited during sexual reproduction Different alleles are produced by mutations, some of which cause changes in the phenotype
61
What's environmental variation
Many characteristics also show environmental variation Becuase they are affected by their surroundings Eg a plant grows according to how much light, water and nutrients it gets
62
What are acquired characteristics
Characteristics that are changed by the environment during the life of the individual eg loss of limb
63
What's discontinuous variation
Is where the data can only take a limited set of values eg number of whole leaves a plant has
64
What's continuous variation
Where data can be any value in any range eg the leaf length in a plant
65
What does a bar chart look like for discontinuous variation
The bars have gaps, you can only have whole numbers
66
What's a bar chart like for continuous data
There are no gaps with bars Values are grouped to make it easier to see patterns In data
67
What's normal distribution for variation
Often forms a bell shaped curve (goes up and then down) Called normal distribution Becuase it's what's expected for a large amount of data for a characteristic where: The most common value is the middle value in the whole range The further a value is from the median, the fewer individuals have that value

Biology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions