DNA Flashcards
What are nucleotides made up of?
Phosphate, Deoxyribose Sugar and one of the four bases
Name the four bases
Adenine (A), Thymine (T), Guanine (G), Cytosine (C)
What are the complementary bases
Adenine and Thymine come together to make (A-T)
Guanine and Cytosine come together to make (G-C)
How many chromosomes are there in a human cell?
46 chromosomes, 23 pairs
How many chromosomes in an ova or sperm? Or a gamete
23 only one of each pair
What do the initials DNA represent?
Deoxyribonucleic Acid
What are the building blocks of DNA and the molecules inside them?
Nucleotides
- Phosphate
- Deoxyribose Sugar
- Base
In what year did scientists know about DNA?
1953
C stands for
Cytosine
G stands for
Guanine
What are the rungs of the ladder made up of
Hydrogen bonds and complementary bases.
What molecules make the upright of the ladder?
Group Phosphate and deoxyribose sugar
What is the molecules upright to which the rungs are joined?
The deoxyriboseSugar
The shape of the DNA is often referred to as a…
Double helix
Where is DNA found?
The nucleus of the cell
How many chromosomes are in the nucleus?
46
What are chromosomes made up of?
Genes
What are genes?
A small piece of DNA that carries the information for a certain trait
T stands for
Thymine
A stands for
Adenine
Nucleotide
The building blocks of DNA
Complementary Base Pairing
A-T G-C
Four scientists who helped discover DNA
Crick
Watson
Franklin
Wilkins
Karyotype
A picture of a person chromosomes. It also contains the number and appearance of a cell.
What is DNA
A compound
How are the bases joined?
By hydrogen bonds
In DNA replication what is a parent strand?
A parent strand is a strand of DNA that breaks of at the origin of replication and duplicates itself.
What was Gregor Mendels contribution to genetics?
He created the basis for the study if modern genetics.
What is a Punnet square?
A Punnet square is a way of displaying all the possible types of offspring.
What is paid attention to when analysing a Karyotype?
Length, position of a centromere, banding pattern and difference between sex cells.
Centromere
Cross section of a chromosome
How many pairs of chromosomes in a human cell?
22 pairs + a pair of sex chromosomes
Male Gender Chromosomes pattern
X+Y
Female gender Chromosomes pair labelled..
X+X
WHEN are the chromosomes visible in a human cell?
When they are dividing.
Which type of cells are best to see under a microscope?
Onion is the most easiest to see
When are chromosomes present in the cell?
Always
Mitosis
Replication of itself exactly. Like snails
Single duplication of a cell and all its parts, they have the same genetic code.
Meiosis
Has two divisions and creates two daughter cells. Meiosis creates gametes which are sex cells. Every cell that is produced by meiosis is different genetically.
How many chromosomes are there in the duplicate cell that has been through the process of mitosis?
46
How many chromosomes are there in the 4 cells that has been through the process of meiosis?
23 chromosomes (gamete)
What type of process is mitosis?
Continous
Mitosis Process
- Chromosomes replicate to become double stranded.
- Double stranded chromosomes become visible.
- Double stranded chromosomes line up along the equator of the cell.
- Chromosomes move to opposite ends of the cell.
- Two nuclei form each with the same number of chromosomes with complete sets.
- Membranes form separating the two nuclei into two daughter cells.
Meiosis Process
- Pairs of double stranded chromosomes line up.
- One double stranded chromosome of each pair moves to each pole.
- Two cells are formed.
- Double stranded chromosomes line up.
- Chromatids separate and move to poles.
- Four cells result with the number of chromosomes in gametes or one set.
Similairties between Mitosis and Meiosis
- Produce new cells and replicate genetic material.
- Cells are reproduced.
- The cell must duplicate DNA.
- They both duplicate to create DNA
How many cells are produced with one event of mitosis?
Two
How many cells are produced with one event of meiosis?
Four
Where does mitosis take place?
All over the body
Where does meiosis take place?
Sex organs such as the ovaries and the testicles.
What is the aim of mitosis?
Cell growth and general body growth and repair of the body.
What is the function of meiosis?
Cells for sexual reproduction
What type of cells does meiosis create?
Gametes
What is a chromatid?
One of the strands following replication
Making copies of DNA is sometimes called..
Replication
Why is it essential that chromosomes replicate?
When the cell divides, the new cell formed must receive a copy of each chromosome genetic material. If DNA did not replicate the daughter cells have the same genetic material. Everyone would be the same!
Define haploid
23 or N
A gamete has 23 chromosomes in total. This is the haploid number.
Why is it important that the number of cells are reduced when a gamete is created?
When the sex cells come together in reproduction to form the new cell, they will have a full set of chromosomes and genes from both of the parents.
What are diploid cells?
46 or 2N
Diploid cells are the chromosomes in your body cells. There are 46 chromosomes half of which are from the mother and the other half from the father.
What are haploid cells?
Haploid cells are gametes or sex cells. They have 23 chromosomes and either will have female or male chromosomes.
What happens between mitosis to a cell?
It goes through a life cycle. It goes through stages of replication and also performing it’s function
What do sperm and ova fertilise to make?
Zygote
Who discovered how traits are inherited?
Gregor Mendel, the Father of Genetics
What is genetics the study of?
Hereditary
What is hereditary?
The passing of traits from parent to offspring
What did Mendel study?
Pea Plants
Pure Breeding
When individuals have the same genetic material for a certain trait generation after generation. Eg- Malfoys hair
What is a dominant gene?
The trait that covers up the other so that it can be visible.
What is a recessive gene?
The gene that is covered up and over powered by the dominant gene.
What is a genotype?
What genes (letters) that organism has
Phenotype
What the organism looks like (physical)
TT
Tall (pure)
Tt
Tall (Hybrid)
tt
Short (pure)
Alleles
Different forms of the same genes
Heterozygous
An organism that has two different alleles for a trait
Homozygous
An organism that has the same alleles for a trait
Is DNA an element compound or mixture?
Compound
Finish this base sequence
T C C G
A G G C
A unit made up of sugar molecule attached to a base and to a phosphate group.
Nucleotide
Differences in Mitosis and Meiosis
-Mitosis produces two cells with one division and meiosis produce four new cells.
-Mitosis takes place all over the body and meiosis takes place in the sex cells.
-Aim of mitosis is cell growth and repair of the body.
-The chromosome number in meiosis is reduced by half, the chromosome number in mitosis stays the same.
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