DNA, Genes, Cell Division, and Inheritance

Flashcards generated from lecture notes on DNA, Genes, Cell Division, and Inheritance.

DNA (Deoxyribonucleic Acid)

A molecule that carries the instructions that make you who you are.

Double Helix

Shape of the DNA – like a twisted ladder.

Nucleotides

Building blocks of DNA; made of a sugar, phosphate, and a base.

Bases in DNA

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

Gene

A section of DNA that gives instructions to make a protein.

Chromosomes

Long strands of DNA; we have 46 total (23 pairs).

Autosomes

The first 22 pairs of chromosomes (non-sex).

Sex Chromosomes

The 23rd pair of chromosomes; XX=female, XY=male.

Nucleus

The control center of the cell, holds DNA.

DNA (Simple Definition)

The code that tells your body how to grow.

Chromosomes (Simple Definition)

Bundled DNA in the nucleus.

Gene (Simple Definition)

A tiny part of DNA with instructions for a trait.

Nucleus (Simple Definition)

The part of the cell that controls everything.

Alleles

Different versions of a gene; one from mum, one from dad.

Homozygous

Same alleles (BB or bb).

Heterozygous

Different alleles (Bb).

Genotype

Your genetic code (letters).

Phenotype

What you actually look like (trait).

Dominant allele

Only need one copy to show the trait.

Recessive allele

Need two copies to show the trait.

Allele (Simple Definition)

A type of a gene (like chocolate or vanilla).

Dominant (Simple Definition)

Strong gene – shows up even if only one.

Recessive (Simple Definition)

Hidden unless there are two.

Genotype (Simple Definition)

The letters you have (BB, Bb, bb).

Phenotype (Simple Definition)

What you look like (blue eyes, brown hair).

Homozygous (Simple Definition)

Same letters (BB or bb).

Heterozygous (Simple Definition)

Different letters (Bb).

Mitosis

Happens in body cells (skin, bone).

Mitosis Result

Makes 2 new cells that are exact copies.

Mitosis Purpose

Used for growth and repair.

Mitosis Chromosome Count

Keeps 46 chromosomes.

Meiosis

Happens in sex cells (sperm/egg).

Meiosis Result

Makes 4 cells, all different.

Meiosis Chromosome Count

Each has 23 chromosomes.

Meiosis Purpose

Used for reproduction.

Mitosis (Simple Definition)

One cell → two same cells (body).

Meiosis (Simple Definition)

One cell → four different sex cells.

Punnett Square

A box used to predict the possible combinations of offspring from two parents.

Co-Dominance

Both traits show up.

Sex-Linked Traits

Found on the X chromosome.

Pedigree

A family tree that shows who has a certain trait.

Carrier

Has the gene but doesn’t show the trait.

Mutation

A change in DNA.

Karyotype

A picture of all 46 chromosomes.

Autosomes (Karyotype)

First 22 pairs of chromosomes in a karyotype.

Sex Chromosomes (Karyotype)

Pair 23 in a karyotype, determines sex.

Down Syndrome

Extra chromosome 21.

Turner Syndrome

Only one X chromosome.

Klinefelter Syndrome

XXY chromosomes.

Nitrogenous bases

Adenine, Thymine, Guanine and Cytosine