Science- Topic 4 Lesson 2 & 3

RNA

The blueprint is transferred from the nucleus to the ribosome by a different nucleic acid called _________ (ribonucleic acid).

homologous chromosomes

The chromosomes you get from your parents come in pairs, called _______________________________, that contain the same genes.

mitosis

The majority of our body cells divide to make two genetically identical new cells in a process called _________________: the cell's nucleus divides into two new nuclei and identical copies of the parent cell's genetic material are distributed into each daughter cell.

DNA

Your "blueprint" is found in the nucleus of each cell in the form of ___________. This (deoxyribonucleic acid) is the genetic material that carries information about an organism and is passed from parent to offspring.

mitosis, meiosis

______________ produces two identical daughter cells with the same DNA as the parent cell. The sex cells produced by _____________, however, are not genetically identical.

transfer RNA (tRNA)

_________________ carries amino acids to the ribosome during protein synthesis.

messengar RNA (mRNA)

___________________ carries copies of instructions for the assembly of amino acids into proteins from DNA to ribosomes in the cytoplasm.

geneticists

_______________________ study how traits are inherited in order to trace their genetic origin and predict how they may be passed on to future generations.

1) formation of mRNA 2) ribosomes attach to mRNA 3) tRNA brings the correct amino acid 4) protein chain is formed

List the process in which protein synthesis happens:

larger chromosomes, trait

Chromosomes are different sizes. ____________________ contain more genes than smaller chromosomes. Each gene contains instructions for coding a particular ____________.

cell cycle, X

Chromosomes are made in the beginning of the _______________, the series of events in which a cell grows, prepares for division, and divides to form daughter cells. During this time, the chromosome gets its characteristic ______ shape.

23, 23

During fertilization, you receive ___________ chromosomes from your father and __________ chromosomes from your mother.

nitrogen bases

Each gene consists of hundreds or thousands of ___________________________ arranged in a sequence.

RNA contains the sugar ribose instead of deoxyribose.

Even though both RNA and DNA are nucleic acids, they have some differences. One difference is that:

genes, chromosomes

Every living thing needs instructions to live. Without these instructions, living things would not be able to grow and function. These instructions are located on _____________. Genes are located on __________________.

RNA has the nitrogen base uracil, while DNA has thymine. RNA is a single strand, while DNA is a double strand.

What are some similarities and differences between DNA and RNA?

1) Chromosome pairs come together and cross over. 2) Cell divides into two daughter cells. 3) Chromosome splits into two chromatids. 4) Four daughter cells are formed.

What are the four steps of meiosis in order?

meiosis and mitosis

What are the two main types of cell division?

meiosis

What form of cell division is this?

mitosis

What form of cell division is this?

A protein breaks the DNA strand in half—at the structure's weakest point—between the nitrogen bases.

What happens after the double helix untwists in DNA replication?

It begins when the double helix untwists.

When does DNA replication begin?

Each sibling comes from a different egg and a different sperm. When each sex cell is created, it is genetically unique.

When you are born, why do you not look identical to your parents or your siblings (even twins)?

sex cells, body cells

While meiosis forms ____________, mitosis forms new _________________.

codon

A ________________ is a sequence of three bases that codes for one amino acid.

pedigree

A ___________________ is a tool that geneticists use to map out the inheritance of traits. The diagram shows the presence or absence of a trait according to the relationships within a family across several generations.

allele combinations

Because more than one gene is present on the 23 pairs of chromosomes, there is a wide variety of ________________________.

adenine (A), thymine (T), guanine (G), and cytosine (C)

DNA has four nitrogen bases:

Traits are transferred to offspring during fertilization when the egg and the sperm come together. Traits are found on the genes in the sex cells of the parents (eggs and sperm).

How are the traits transferred from the parents to the offspring during reproduction? Where were those traits found?

The cells that were formed have less genetic material and the genetic material inside each cell is different.

How is the genetic material of the parent cell different from the four cells that are formed?

When you unzip a zipper, the 2 halves part. In the same way when DNA separates, it breaks along the center into 2 halves.

How is the separation of DNA like a zipper?

46

How many chromosomes do humans have?

They look at the code on the gene and each inherited chromosome. If each gene has identical code in the same allels, the individual is homozygous for the trait. If the genes have different codes, the individual is heterozygous for the trait.

How would geneticists—people who study genes—know whether an organism is homozygous or heterozygous for a certain trait by examining the chromosome pair?

squares, circles

In a pedigree, males are represented with _____________ and females with _______________. One horizontal line connects the parent couple and another line leads down from the parents to their children.

body cell

In an organism that is reproduced sexually, a ________________ has twice as many chromosomes a sex cell.

20,000 and 25,000

In humans, between _____________ and ___________ genes are found on the 46 chromosomes.

80

Other organisms have different numbers of chromosomes, and there is a great variety. For example, mallard ducks have _________ chromosomes.

37 trillion

Scientists estimate that humans are made of approximately __________________ cells.

meiosis

Sex cells (sperm and egg) are formed through a very specialized process called ____________, during which the number of chromosomes is reduced by half. This creates new cells with half as many chromosomes as the parent cell.

identical DNA, chromosomes

The process of DNA replication, or copying, ensures that each chromatid of a chromosome has _______________________. During cell division, ____________________ split.

nucleus

The process of protein synthesis starts in the _________________, where the DNA contains the code for protein.

unzipping the DNA

The separation that happens in DNA replication is often referred to as "______________________."

sugars, phosphates, and nitrogen bases

The structure of DNA consists of _______________, _______________, and ___________________. These things make up the sides of the ladder and the rungs of a DNA ladder.

23, 23

The zygote gets two sets of chromosomes—one set from the sperm and one set from the egg. Human eggs, for example, contain ______ total chromosomes in a set and sperm contain _______ total chromosomes in a set. So, each of your body cells contains one set of chromosomes from your mother and another set from your father for a total of 46 chromosomes.

20, protein synthesis

There are only ________ amino acids in the human body, but your body can combine them in thousands of ways to make many different types of proteins needed to carry out cell processes. Inside the cell, amino acids link to form proteins through a process called ________________.

messengar RNA and transfer RNA

There are two main types of RNA involved in protein synthesis:

chromosomes

Today, scientists know that genes are segments of code that appear on structures called _____________________. These threadlike structures within a cell's nucleus contain DNA that is passed from one generation to the next.