Cell Reproduction, DNA Replication, Gene Expression, Cancer, and Genetics

A comprehensive set of 170 flashcards covering cell reproduction, DNA replication, gene expression, cancer mechanisms, and basic genetics principles.

What is cell division?

Cell division is when one cell splits to make new cells.

What are the two types of cell division?

Mitosis and meiosis.

What does mitosis produce?

Identical body cells.

What does meiosis produce?

Sex cells with half the chromosomes.

What is Chromatin?

Loose, thread-like DNA found in the nucleus before cell division.

What is a Chromosome?

Tightly packed DNA seen during cell division.

What are Sister chromatids?

Two identical copies of a chromosome connected at a centromere.

What is a Centromere?

The middle point holding sister chromatids together.

What are Homologous chromosomes?

Pairs of chromosomes (one from mom, one from dad) that carry genes for the same traits.

Are sister chromatids identical?

Yes, sister chromatids are identical.

Are homologous chromosomes identical?

No, homologous chromosomes are similar but not identical.

What are Autosomes?

Chromosomes that are not sex chromosomes.

What are Sex chromosomes?

Chromosomes that determine gender (X and Y).

What are Somatic cells?

Body cells like skin or muscle, which are diploid.

What are Sex cells (gametes)?

Sperm and egg cells, which are haploid.

What does Diploid mean?

Having two sets of chromosomes (2n).

What does Haploid mean?

Having one set of chromosomes (n).

What constitutes the cell cycle?

The life of a cell, from when it forms to when it divides.

What is the longest phase of the cell cycle?

Interphase.

What are the stages of Interphase?

G₁ (cell grows), S (DNA is copied), G₂ (cell prepares to divide).

What is Cytokinesis?

When the cytoplasm splits, forming two new cells after mitosis.

What does the mitotic spindle do?

Moves and separates chromosomes during mitosis.

How does mitosis help in multicellular organisms?

Mitosis helps growth and repair.

What is the purpose of mitosis in single-celled organisms?

For reproduction.

What are the four stages of mitosis?

Prophase, Metaphase, Anaphase, Telophase.

What happens during Prophase?

Chromosomes form, spindle appears, nuclear membrane disappears.

What happens during Metaphase?

Chromosomes line up in the middle.

What occurs during Anaphase?

Sister chromatids separate to opposite sides.

What happens in Telophase?

New nuclei form; the cell starts to split.

How many chromosomes do haploid and diploid cells have?

Haploid = 13, Diploid = 26.

How many chromosomes do somatic and gamete cells have?

Somatic = 30, Gametes = 15.

If a gamete has 8 chromosomes, how many do somatic cells have?

Somatic cells = 16.

If somatic cells have 24 chromosomes, how many pairs are there?

12 pairs.

What are the haploid and diploid chromosome numbers in humans?

Haploid = 23, Diploid = 46.

What is Meiosis?

Meiosis makes gametes (sperm and eggs).

Why is it called reduction division?

It cuts chromosome numbers in half.

What is the significance of genetic variety in meiosis?

It mixes up genes for genetic variety.

What are the two processes that occur in meiosis?

Crossing over and independent assortment.

Does DNA replicate before meiosis?

Yes, DNA replicates once in the S phase before meiosis.

What are the stages of Meiosis I?

Prophase I, Metaphase I, Anaphase I, Telophase I.

What are the stages of Meiosis II?

Prophase II, Metaphase II, Anaphase II, Telophase II.

What is Crossing over?

When homologous chromosomes trade DNA pieces.

When does crossing over happen?

In Prophase I.

What does independent alignment refer to?

Chromosomes line up randomly.

What is the result of independent alignment?

Creates genetic variation.

How similar are siblings genetically?

Two siblings have almost zero chance of being genetically identical unless they’re identical twins.

What happens during Anaphase I?

Homologous chromosomes separate (still double).

What happens during Anaphase II?

Sister chromatids separate (single copies now).

How many cells does mitosis produce?

2 identical diploid cells.

How many cells does meiosis produce?

4 unique haploid cells.

What is the maximum chromosome count in each gamete?

16 when starting with 32 chromosomes.

Who has control over DNA replication to make proteins?

No, replication isn’t needed for protein-making.

What is a nucleotide?

The monomer of DNA, consisting of sugar, phosphate, and base.

What is the structure of DNA?

DNA is a double helix with sides made of sugar and phosphate, and steps made of base pairs (A–T, C–G).

What is RNA?

A single-stranded nucleic acid involved in protein synthesis.

Where is RNA found?

In the nucleus and cytoplasm.

What are the types of RNA?

mRNA, tRNA, rRNA.

What distinguishes DNA from RNA?

DNA is double-stranded, while RNA is single-stranded.

What is the function of DNA?

Stores genetic code.

What is the function of RNA?

Helps make proteins.

What happens during DNA replication?

A full copy of DNA is made before cell division.

What are the steps of DNA replication?

DNA unwinds, strands separate, new nucleotides attach, and two identical DNA molecules form.

What is protein synthesis?

Making proteins through transcription and translation.

What is Transcription?

The process of copying a gene from DNA to mRNA.

How does mRNA function?

Carries DNA’s code to ribosomes for protein synthesis.

What is a Codon?

A 3-base sequence on mRNA that codes for one amino acid.

What is Translation?

Reading mRNA to build a protein.

How do mutations occur?

Changes in DNA caused by radiation, chemicals, or errors in replication.

How can mutations affect proteins?

Mutations can change proteins or stop them from working.

What is a Somatic mutation?

Mutations affecting only that body cell.

What is a Gamete mutation?

Mutations that are passed to offspring.

What steps are involved in the genetic code process?

DNA holds the code, transcription makes mRNA, mRNA goes to the ribosome, and translation builds protein from amino acids.

What does a mutation cause?

A change in DNA that can affect protein function.

What are proto-oncogenes?

Genes that turn cell division on when needed.

What are tumor suppressor genes?

Genes that turn cell division off when not needed.

What happens if proto-oncogenes mutate?

They stay “on,” causing uncontrolled growth.

What happens if tumor suppressor genes mutate?

The “off” switch is broken.

What are the stages of cancer development?

Initiation (one cell mutates), Promotion (cells divide faster), Progression (tumor becomes aggressive).

What is metastasis?

The ability of cancer cells to spread and become motile.

What are the characteristics of cancer cells?

Divide uncontrollably, ignore signals, and can spread.

What are the types of tumors?

Benign, in situ, and malignant.

What is benign tumor?

A tumor that stays in one spot.

What is a malignant tumor?

A tumor that spreads to other tissues.

What are common treatments for cancer?

Surgery, chemotherapy, radiation, immunotherapy.

When is chemotherapy recommended?

When cancer has spread.

Why does chemotherapy affect hair cells?

Chemotherapy affects all fast-dividing cells, leading to hair loss.

What is immunotherapy?

A treatment that helps the immune system target cancer while chemotherapy kills cells directly.

What is a Gene?

A piece of DNA that codes for a specific trait.

What is an Allele?

Different versions of a gene.

What is a Dominant allele?

An allele that always shows up when present.

What is a Recessive allele?

An allele that only shows up if two copies are present.

What is Genotype?

The genetic makeup of an organism.

What is Phenotype?

The physical appearance of an organism.

What is Homozygous dominant?

Having two dominant alleles.

What is Homozygous recessive?

Having two recessive alleles.

What is Heterozygous?

Having one dominant and one recessive allele.

What do Punnett Squares represent?

The possible genotypes of offspring.

How many gametes does homozygous dominant produce?

One kind of gamete.

How many gametes does homozygous recessive produce?

One kind of gamete.

How many gametes does heterozygous produce?

Two kinds of gametes.