Cell Membrane and Proteins Overview

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Questions and Answers

What role does cholesterol play in the cell membrane?

Promotes cell division

Facilitates nutrient transport

Acts solely as an energy source

Helps maintain membrane fluidity (correct)

Which of the following describes receptor proteins?

Are involved primarily in transporting molecules

Allow certain cells to respond to specific chemicals (correct)

Always allow any molecule to bind

Can only bind to one specific molecule

What is the function of junction proteins?

Transport materials across the cell membrane

Facilitate chemical reactions inside the cell

Bind cells together (correct)

Allow cells to be recognized by the immune system

Which process describes the folding of a membrane to transport materials?

Cytosis Signup and view all the answers

What is the primary function of the central vacuole in plant cells?

Storage of water and other molecules Signup and view all the answers

During which phase do homologous pairs of chromosomes form and crossing over occurs?

Prophase I Signup and view all the answers

What happens to the nuclear envelope in Prophase I?

It breaks up. Signup and view all the answers

What results from the pulling apart of homologous pairs during Anaphase I?

Each daughter cell receives one chromosome from each pair. Signup and view all the answers

What is the state of the cell when the spindle attaches to the centromeres?

The cell is rounding up. Signup and view all the answers

How many chromosomes does each daughter cell have after Anaphase I, relative to the parent cell?

Half the number of chromosomes as the parent cell. Signup and view all the answers

What does glycolysis primarily break down?

Glucose Signup and view all the answers

How many ATP molecules are produced net from glycolysis?

2 ATP Signup and view all the answers

In which cellular location does glycolysis occur?

Cytoplasm Signup and view all the answers

How many ATPs are required to initiate the glycolysis process?

2 ATPs Signup and view all the answers

What is produced from the reduction of NAD+ during glycolysis?

NADH Signup and view all the answers

What is the initial substrate molecule in glycolysis?

Glucose Signup and view all the answers

What molecules are the end products of glycolysis?

2 pyruvate and 2 NADH Signup and view all the answers

Which of the following is true about the energy investment phase of glycolysis?

It requires energy Signup and view all the answers

What term describes an organism with different alleles at a particular locus?

Heterozygote Signup and view all the answers

Which type of allele is not fully expressed in a hybrid?

Recessive allele Signup and view all the answers

What does the principle of independent assortment state?

Alleles at one locus are inherited randomly from each parent. Signup and view all the answers

Which process studies the inheritance of two traits simultaneously?

Dihybrid cross Signup and view all the answers

Which term refers to a single genotype influencing several traits?

Pleiotropy Signup and view all the answers

What are traits influenced by multiple genes referred to as?

Polygenic traits Signup and view all the answers

In terms of gametes, how are alleles carried?

Haploid only Signup and view all the answers

What does dependent assortment imply about alleles at different loci?

They can be linked and inherited together. Signup and view all the answers

What is the term for a fertilized egg cell that contains alleles from both parents?

Zygote Signup and view all the answers

Which of the following best exemplifies a polygenic trait in humans?

Eye color Signup and view all the answers

What is formed when a spermatozoan and an ovum fuse?

Diploid zygote Signup and view all the answers

What phase follows the formation of a diploid zygote in development?

Cell cycle Signup and view all the answers

What is a characteristic of true breeding varieties in genetics?

They reproduce identical phenotypes over generations. Signup and view all the answers

In a monohybrid cross, which generation is referred to as the F1 generation?

Offspring of the parental generation Signup and view all the answers

What does a Punnett square layout help to identify?

Genetic information combinations Signup and view all the answers

Which term refers to a specific quality or trait that is potentially variable in an organism?

Character Signup and view all the answers

What does phenotype relate to in an organism?

Observable characteristics influenced by both genotype and environment Signup and view all the answers

What type of organism is produced from the fusion of gametes?

Diploid multicellular organism Signup and view all the answers

What defines a heterozygous organism?

It has different alleles at a locus. Signup and view all the answers

Which type of organism is generated during meiosis in context of gametes?

Haploid gametes Signup and view all the answers

In the inheritance of traits, what is identified as a dominant particle?

It determines a specific color regardless of other alleles. Signup and view all the answers

What is an allele?

A variant of a gene found at a specific locus. Signup and view all the answers

Which of the following describes a hybrid offspring?

Offspring resulting from two different varieties Signup and view all the answers

What is the function of a gene in genetics?

It is a sequence of DNA responsible for a specific trait. Signup and view all the answers

Study Notes

Cholesterol

Cholesterol is a lipid found in animal cells, it is non-polar
Cholesterol helps maintain membrane fluidity
Cholesterol is important for cell function
Cholesterol is difficult to transport because it doesn't dissolve in water

Receptor Proteins

Receptor proteins are located on the cell membrane
They bind to specific chemicals (e.g. tastebud receptors)
They allow cells to respond to specific chemicals

Enzymes

Enzymes are proteins that facilitate reactions
They are essential for many cellular processes

Identification Markers

Identification markers are proteins that allow cells to be recognized by other cells
For example, blood types

Junction Proteins

Junction proteins bind cells together

Cytosis

Cytosis is a type of transport that involves the folding of the cell membrane
Endocytosis: bringing material into the cell
Exocytosis: expelling material from the cell

Plant Cells

Plant cells are multicellular
Plant cells contain a cell wall and a central vacuole
The central vacuole is a storage space for water and other molecules
The cell wall provides structural support for the plant

Glycolysis

Glycolysis is a metabolic pathway that breaks down glucose into two molecules of pyruvate
Glycolysis can operate with or without the presence of oxygen
Requires an investment of 2 ATP molecules to begin the process
The process can be divided into three stages:
- Stage 1 begins with glucose (6 carbon molecules) and uses 2 ATP molecules to generate more energy, thus becoming ADP
- Stage 2: glucose is broken down into two 3-carbon molecules (G3P) with the help of phosphate groups from ATP
- Stage 3: Each G3P molecule contains a phosphate and NAD+
  - NAD+ gets reduced (an electron is added) into NADH
  - 2 ADP molecules turn into 2 ATP molecules
  - The two G3P molecules turn into pyruvate
Glycolysis results in a net energy gain of 2 ATP molecules
It occurs in the cytoplasm of both prokaryotic and eukaryotic cells

Meiosis

Meiosis is a process of cell division that produces gametes (sex cells)
It involves two rounds of division, resulting in four haploid daughter cells
Each daughter cell has half the number of chromosomes as the parent cell
Meiosis is essential for sexual reproduction

Stages of Meiosis I

Prophase I: Chromosomes condense next to their homologue forming pairs (homologous pairs) and become visible, the cytoskeleton breaks down, the nucleolus disappears and the spindle starts to form
Metaphase I: Homologous pairs line up along the metaphase plate.
Anaphase I: Homologous pairs of chromosomes are pulled apart and pulled to opposite ends of the cell
Telophase I: Each daughter cell receives one chromosome (with two chromatids) from each pair.

Meiosis II

Prophase II: Chromosomes condense, spindle fibers form, and the nuclear envelope breaks down.
Metaphase II: Chromosomes line up at the metaphase plate.
Anaphase II: Sister chromatids of each chromosome separate and move to opposite poles of the cell.
Telophase II: The nuclear envelope reforms.
Cytokinesis: The cytoplasm divides, forming four haploid daughter cells.

Haploid and Diploid

Diploid cells have two sets of chromosomes (2n), one from each parent.
Haploid cells have one set of chromosomes (n).

Sexual Reproduction

Haploid gametes from each parent fuse (fertilization) to create a diploid zygote
The zygote goes through mitosis to develop into a multicellular organism

Sexual Reproduction in Animals

Diploid zygotes go through meiosis to produce haploid gametes
Diploid offspring go through mitosis to develop into a new organism

Sexual Reproduction in Plants

Zygotes go through mitosis to produce a haploid, multicellular organism
The haploid organism produces gametes through meiosis
Gametes fuse through fertilization to create a new diploid organism

Genetics

Character (trait): A potentially variable quality or quantity in an organism
True-breeding variety: When new generations after reproduction have the same phenotype
Hybrid offspring: Offspring of two different varieties
Monohybrid cross: Studying the inheritance of a single character in a hybridization experiment

Genetics Terms

Parental (P) generation: The original parents
First filial (F1) generation: Offspring of the P generation
Second filial (F2) generation: Offspring of the F1 generation
Gene: A sequence of DNA that codes for a specific trait
Locus: The specific location of a gene on a chromosome
Allele: An alternative form of a gene
Genotype: The genetic makeup of an organism
Phenotype: The observable characteristics of an organism
Homozygous: Two identical alleles at a particular locus
Heterozygous: Two different alleles at a particular locus
Dominant allele: An allele that is fully expressed in a heterozygote
Recessive allele: An allele that is not fully expressed in a heterozygote
Pleiotropy: One gene affects multiple traits
Dihybrid cross: Studying the inheritance of two traits in a hybridization experiment
Independent assortment: Alleles at different loci are inherited independently of each other
Dependent assortment: Alleles at different loci are inherited together
Polygenic traits: Traits influenced by multiple genes (e.g., skin color)

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Description

This quiz covers key concepts related to the cell membrane and its components, including cholesterol, receptor proteins, enzymes, and various cellular functionalities. Understand how these elements contribute to cell behavior and interaction. Perfect for students studying cell biology.