Genetics Quiz 1: Miosis, Mitosis, Human Genome, RNA, DNA

Know how to draw nucleotide, meiosis, mitosis, DNA, RNA

What is a Genome?

an organism's full set of deoxyribonucleic acid (DNA)

What are nitrogenous bases?

Molecules inside DNA
The human genome is made of 3 billion ATCGS

What are the nitrogenous bases in DNA?

Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

How many chromosomes in a human cell?
What are they called ?

46, that are arranged in pairs
homologous

How are ATCGs organized in terms of % ?

99% of DNA is non coding 1% holds 20, 000 genes

What are genes?

Segments of DNA that code for a protien

What is DNA made of? What are the parts?

building blocks called nucleotides:

What are the two types of nitrogenous bonds?

Pyrimidines: one ringed structure (cytosine, guanine)
Purines: two ringed structures (adenine, thymine)
(Pure As Gold)

Describe the structure of DNA in terms of shape and where the parts of the nucleotides are in this structure.

Double helix (twisted ladder)
Two strands of DNA that run anti parallel to each other
The sugar phosphate makes up the sides of the ladder
ATCGs make up the rungs of the ladder

Who discovered DNA structure?

James Watson, Francis Crick, (Supported by research done by Rosalind Franklin)

Complimentary Base Pairing

Adenine (A) pairs with Thymine (T) → 2 hydrogen bonds
Guanine (G) pairs with Cytosine (C) → 3 hydrogen bonds
RNA exception:
Thymine (T) is replaced by Uracil (U) → A pairs with U

What is DNA

DNA (Deoxyribonucleic Acid) is the molecule that carries genetic information in almost all living organisms. It's essentially the "instruction manual" for life.

What is RNA?

RNA (Ribonucleic Acid) is a molecule similar to DNA that helps carry out the instructions stored in DNA. It's crucial for making proteins and regulating some cellular functions.

Name one similarity and 3 difference between DNA and RNA

both are nucleic acid
RNA has Uracil instead of Thymine
RNA is single stranded
RNA has ribose sugar (not deoxyribose)

What are the Nitrogenous bases in RNA?

Adenine (A)
Uracil (U)
Cytosine (C)
Guanine (G)

What is the goal of Meiosis?

To produce genetically unique sex cells called gametes that have half the number of chromosomes as the rest of the cells in the body.

What do we call "normal" cells in our body?

somatic

What do gametes come together to produce

Sperm + Egg = Zygote

What does Meiosis to a population? How?

Increases genetic variation in a population
When genetically unique gametes fuse to create a new individual called a zygote, the zygote will have a unique combination of DNA

Gamete

A sex cell that carries half the number of chromosomes (haploid) of a normal body cell.

Another word for egg?

Ovum

homologous chromosomes?

Chromosomes that have the same sequence of genes and the same structure (matching)

What are sister chromatids?

2 halves of a double stranded chromosomes (x

Meiosis 1:

Reduction Division
Purpose: Reduce chromosome number from diploid (2n) to haploid (n).
Result: Two haploid daughter cells, each with half the number of chromosomes as the original cell, but each chromosome still has two sister chromatids.

Interphase 1 (meiosis)

DNA is replicated so single stranded chromosomes become double stranded

Prophase 1

Homologous chromosomes pair up side by side (Synapsis)
and form tetrad or bivalents
synapsis and crossing over (exchange of DNA)

Chiasmata

structure that holds bivalents together during crossing over

Metaphase 1:

Bivalents line up at the equator or metatorial plate
Random orientation occurs (random arrangement of paired chromosomes in the middle of the cell)

Anaphase 1:

The homologous chromosomes pairs separate from each other due to the shortening of spindle fibres

Telophase 1:

nuclear membrane reforms
cells have half the number of chromosomes as they did at the beginning of meiosis
before the were diploid (2n) and now they are haploid (n)

Diploid and Haploid

A diploid (2n) cell has two sets of chromosomes (one from each parent), while a haploid (n) cell has only one set, like gametes.

meiosis 2:

cells are haploid
stages of meiosis 2 is the same as mitosis,
Interphase 2 is very short and no DNA replication occurs

What happens at the end of Meiosis 2:

the original cell splits up into 4 haploid cells, each with a unique mixture of maternal and paternal chromosomes.

What is complementary base pairing in double stranded DNA?

specific way nitrogenous bases pair between two DNA strands
A w T
G w C

What type of bonds connect the base pairs and why are they important

hyrdogen bonds
A&T w 2
G&C w 3
Hold DNA strands together
Allow them to separate for replication
ensure accurate base pairing to preserve genetic information

What does running antiparallel do for the DNA in terms of structure

maintains the stability of the double helix