DNA, Chromosomes and Genes Flashcards
do it now hoe or else
What does DNA stand for?
Deoxyribonucleic Acid
What is DNA?
DNA is the chemical
component found in the
nucleus that stores coded
instructions
It has the code for making
all the different proteins
and cells
What is the shape of DNA?
DNA structure is shaped as a double helix.
The structure is described as being anti-parallel - the two
strands run in opposite directions.
What are the basic units of DNA called?
Nucleotides
There are 3 components to a
nucleotide, what are they?
Sugar, phosphate, nitrogenous bases
These are the backbone of
DNA (sugar and phosphate).
What are the 4 nitrogenous bases?
- Adenine (A)
- Thymine (T)
- Cytosine (C)
- Guanine (G)
Nitrogenous bases always pair
according to the base pairing
rule, which is?
A is chemically attracted to T
C is chemically attracted to G
What is a chromosome?
A chromosome is a strand of
DNA that is encoded with
genes.
Made of DNA wrapped around
proteins.
Humans have 23 pairs (46)
chromosomes in our cells.
Chromosome structure
Can be a single
chromosome or
bivalent
chromosome.
Bivalent = 2 strands
of DNA (X shaped)
Number of
chromosomes =
number of
centromeres
Chromosomes have strands called chromatids and a
centromere that holds the chromatids together.
Name the types of chromosomes
Sex chromosomes
* Chromosomes involved in sex
determination
* 23rd pair in humans
* XX = female, XY = male
Autosomal chromosomes
* any chromosomes other than
the sex chromosomes.
* First 22 pairs in humans
What is a karyotype?
A picture of all the homologous chromosomes in a
cell, arranged from largest to smallest.
What is a gene?
A gene is a section of
DNA, which contains a
particular set of
instructions.
Genes are codes which
produce specific proteins.
Specific genes are
located on the same
chromosomes.
Where is DNA found in the cell?
In the nucleus.
What is the sugar found in DNA?
Deoxyribose sugar
