Chromosomes

How many pairs of autosomes do humans have?

22

Humans have 46 chromosomes, so our diploid number is...

2n = 46

Why is DNA attracted to histones?

Because DNA is negatively charged, whereas histones are positively charged.

Why are gametes considered haploid cells?

Because the chromosomes in sperm and egg cells do not come in pairs, but rather only have a single chromosome from each pair.

What is the function of a fifth histone?

Further wrapping (packaging) of the DNA molecule and eventually to the highly condensed or supercoiled chromosomes.

Why are there two of each chromosome?

One's from the mother, the other's from the father.

How did Cairns use his technique?

To demonstrate that a bacterium's chromosome is made up of a single circle of DNA and that it is replicated by being unzipped.

How does the packaging of DNA regulate the transcription process?

When DNA is wrapped around the histones and then further wrapped in even more elaborate structures, it is inaccessible to transcription enzymes.

Human males have one...

X chromosome and one Y chromosome.

In human females there are two...

X chromosomes.

The term diploid is used to describe...

a nucleus that has chromosomes organized into pairs of homologous chromosomes.

A karyogram is...

a representation of the chromosomes found in a cell arranged according to a standard format.

The nucleoid region of a bacterial cell contains...

a single, long, continuous, circular thread of DNA.

1). If there is no pattern to the frequency of a trait between females and males, it is most likely to be...

an autosomal trait.

Sister chromatids form a single chromsome...

and are attached at the centromere.

Any chromosome that is not a sex chromosome is called an...

autosome, or autosomal chromosome.

Prokaryotes can reproduce using...

binary fission.

The DNA of eukaryotic cells most often occurs in the form of...

chromosomes.

The X chromosome is longer than the Y chromosome, and...

contains many more genes.

Most cells in the human body are...

diploid cells.

A haploid cell has...

half the usual number of chromosomes.

Gametes are...

haploid cells.

A human's 46 chromosomes can be grouped into 23 pairs of chromosomes called...

homologous chromosomes.

What is involved in Cairns' technique?

injecting radioactive materials into the DNA samples that will expose the film faster.

It is rare for eukaryotes to have one chromosome, but...

male bees, wasps and ants can.

A nucleosome consists of...

of two molecules of each of four different histones.

If a trait or gene is described as autosomal, its locus is on...

one of the 22 pairs of autosomes, not on the sex chromosomes.

Autoradiography is a technique in which

radiation from a substance is captured on photographic film or by a camera sensor.

organisms such as plants and animals more frequently reproduce using...

sexual reproduction.

Homologous means...

similar in shape and size, and that the two chromosomes carry the same gene.

\ Although a pair of homologous chromosomes carries the same genes, they are not identical because...

the alleles for the genes from each parent could be different.

Plasmids are not connected to...

the main bacterial chromosome.

A person's karyotype is...

the specific number and appearance of the chromosomes in his or her cells.

Chromosomes take the typical 'X' shape when...

they are preparing to divide.

The 23rd pair of chromosomes are called the sex chromosomes because...

they determine whether a person is a male or a female.

In chromosomes, DNA wraps around the eight protein molecules...

twice.

When sister chromatids separate, they become...

two identical chromosomes.